Windows 10 Wont Boot, How To Fix Master Boot Record

well you guys asked for it so today I'm going to show you how to rebuild an MBR bootloader this turned out being a much bigger project than I originally expected stay tuned [Music] several weeks ago I did a video on how to repair a UEFI partition in that video I said if you guys wanted I would do a video on how to repair an MBR bootloader I got an overwhelming amount of you guys that wanted me to do that video so here it is in that last video I said that repairing an MBR bootloader is easy however I guess it's been a while since I tried to fix an MBR bootloader because it turned out being anything but easy in fact it turned out to be way harder than I remember it being but before we get into that we got to pay some bills so check out today's sponsor is your copy of Windows 10 unactivated well it doesn't have to be because with today's sponsor VIP SCD key you can get a valid Windows 10 license for under 20 dollars stop dealing with that stupid watermark on the desktop the valid license for Windows 10. also with an activated copy of Windows 10 10 you can upgrade to Windows 11 for free just go to the link in the description below and pick up a valid Windows 10 license key during checkout use the code cyber CPU for a 25 discount once you have your key go to your activation settings in Windows 10 and click on the link that says change product key enter the product key you just purchased and hit activate now you don't have to deal with that stupid Watermark that come with running an unactivated copy of Windows 10. now on with the video so as I said before it turns out it is way harder to fix an MBR bootloader than it was to rebuild a UEFI like we did a couple weeks ago it's not harder because the tools aren't available to fix it but it's harder because the tools that are available simply don't work here's the thing Microsoft doesn't care about MBR anymore so the tools available to repair an MBR bootloader simply don't work anymore this also seems to be a very well-known problem as you will see from this video the primary tool that we're going to be using to rebuild our bootloader is going to be a command called bootrec and like most commands bootrec has a lot of different switches one of the switches that is necessary to repair an MBR bootloader is fixed boot unfortunately the last version of Windows that that switch actually worked in was 1703 fixed boot is the switch that actually writes the boot sector to the system partition unfortunately if you try to use this switch in recovery on an ISO later than 1703 which came out in 2017 you'll get an error this just simply says access denied unfortunately there's no work around it simply doesn't work now I'm not a conspiracy theorist but this may have something to do with the fact that Microsoft doesn't care about MBR anymore they want everyone on UEFI I mean UEFI is literally a requirement for Windows 11 seven this might have something to do with the fact of why Microsoft has allowed this tool to be broken for over six years so in order to follow this guide you're going to need a Windows 10 ISO of build 1703 or earlier that literally is the only way this guide will work and unfortunately Microsoft purged their download servers of all older builds of Windows 10 before I believe 1909. I can't tell you where to get an ISO for build 1703 or earlier if I did then the YouTube algorithm would more than likely take this video down with claims of software piracy but I'm sure you all know where to get Windows isos if you don't just Google it they're pretty easy to acquire but you know I got lucky and I had build 1703 already burned to a CD that I just ripped to an ISO and I also had build 1507 which was the first public release of windows 10. so I was able to test this guide and build 15 seven and build 1703 and it worked great in both so I'm assuming that it should work in every build in between now I normally recommend against grabbing windows isos from sketchy sources but in this case we really have no choice and luckily we won't actually be installing windows with the iso but instead simply using the recovery that comes on this ISO so it should be okay with whatever Source ISO you can find in that now I'm just going to be throwing this ISO on a USB drive configured with ventoy since I was testing several different builds of Windows 10 rather than make a USB drive out of every build I just threw them all on a ventoy USB drive to make it a little bit easier on myself I did another video a while back showing you how to create a ventoy USB drive and I'll go ahead and Link that video in the description below so you can make your own so find yourself an ISO with Windows 10 build 1703 or earlier and let's jump on the computer and I'll show you how to fix an MBR bootloader but first thing we have to do is break the system because there's no point in fixing a bootloader on a system that boots fine right let's do it okay so here we are in Windows 10 this right here is currently build 22 H2 this is a brand new install it literally has nothing installed on it so what we're going to do is we're just going to create a text document right here and we're going to name this Tech document test and then from here we're going to open this up and we're going to write I guess we fixed it and then I'm going to go ahead and save this and I'm just doing this just so you guys can see that we are dealing with the same version of Windows once we repair it we'll be able to open this test document right here when we get this thing rebooted so the first thing we need to do is go ahead and plug our ventoy CD or USB drive into the computer and then once we do that we can get this thing booted into recovery and we can break it so let's do that now so to get your system booted up into your USB drive you're going to have to follow whatever manufacturer specific things you have to do on your computer in order to get it booted off of a thumb drive on mine I'm just hitting delete to go into the BIOS and then I'm going to overwrite the boot and to do that I'm simply going to go right here go into my boot menu and pick my flash drive right here and then once this thing boots up into recovery I'll meet you there okay so once we're booted up onto the Windows setup CD all you got to do is hit next and then we don't want to hit install now we want to click on repair your computer and then from here we're going to click on troubleshoot we're going to go to the command prompt now we're having to do this from recovery because unfortunately Windows 10 won't allow me to break it from within Windows itself so I had to do it from recovery so what we're going to do is we're going to go to the C drive here and as you can see there's nothing in this drive so if we go directory switch a it'll give us the directory of everything no matter what its attributes are even hidden files and from here we can see we have a couple of files that are pretty important like we have boot manager and we have the boot directory right here now on this system right here boot manager is essentially your boot sector it's located at the very beginning of this partition and it tells the system what to do when it boots now your boot sector is made up of 512 kilobits of data at the very very beginning of the drive and now the 460 kilobyte boot manager is the boot information it tells the system how to boot the remainder of that 512 kilobyte is actually your partition information so it was a little bit difficult to figure out how to break this system so keep in mind this portion of the guide isn't something you should be following this is actually just to break the system so I can show you how to fix it I don't recommend following this part of the guide because there's no reasonable reason to break a bootloader unless of course you're making a YouTube video about it in that case go on ahead and do it but for your system I highly recommend against doing that so what I'm going to do is I'm going to go ahead and just delete a couple of these files and make the system unbootable and then I'll show you how to fix it okay so we're gonna go completely scorched Earth on this one the first thing we're going to do is we're going to remove the boot directory completely and then I'm also going to delete the boot sector which is this boot manager file right here so to do that we use the atrib command and we want to subtract system hidden and read only from the boot manager and then from there we can just delete the boot manager and unfortunately at this point the system won't boot but we're going to go one step even further and we're going to remove the directory we have to use the S switch because the directory has something in it boot and then from there it asks you if you're sure I'm going to hit yes and okay so now when we hit directory switch a you'll see that we're missing a few things so let's get this thing rebooted and we'll go ahead and see if it boots just a spoiler alert it won't [Laughter] so we're gonna fire it up now I'm gonna go ahead and take my USB drive out and we're gonna see what happens might take it a second to fire up but it's not going to take it long to error out and there we go an operating system wasn't found try disconnecting any drives that don't contain an operating system press curlwalt delete to restart and we're essentially non-bootable at this point so I'm going to plug this back in we're going to get back into recovery and I'll show you how to fix it okay so we're back in recovery here we're going to go ahead just like before we're going to hit next and we don't want to install it we want to hit repair your computer and then from there we want to go to troubleshoot and then we want to go to command prompt and here's our command prompt now one thing that I have to add and I should have probably said this earlier in the video is when you're booting from recovery make sure you boot in recovery in MBR because a Windows install CD can both be booted MBR and UEFI you want to make sure not to boot UEFI if you're going to be repairing an MBR bootloader so make sure you just boot into recovery using MBR so let's move on okay so the first thing that we're going to want to do obviously is we have to determine what drives container boot files now I already know this but I'm going to show you the process in which how you can figure this out and to do that all you got to do is type disk part and then once disk part opens up might take a second you can go list disk and this will show you all the different disks that are on the system so obviously here I've got my USB thumb drive which is disk one which is about 60 gigs and then I've got my one terabyte SSD that is my main drive and this is the drive that has all of my different Windows partitions on it so obviously we want disk zero so for that we're going to hit SEL for select disk zero and then from right here we want to see what volumes are available on that disk so we're going to type in list Vol for volume and that's going to show us all of our different volumes and as you can see here we have a virtual dvd-rom and that's for from our ventoy install we have our removable partition this one right here is the USB drive and then you can see these three partitions in the middle we have c e and f now on C drive is a system reserve partition it's only 50 megabytes and then number two is the e Drive which is an ntf partition with 930 gigabytes clearly this one right here is our Windows install and then we have the F Drive which is 522 megabytes now this is going to be our recovery partition for Windows 10. this system reserved partition right here is what Windows uses to kind of hide all the boot files so that they're not on the main partition so you can't actually see this partition from within windows it's a hidden partition so all your boot files are contained on that drive right there so now that we know that we we can go ahead and exit disk part here so once we exit we'll remember that that one was C so when we go to the C drive you'll see that it actually has nothing on it because all the files on it are hidden so if we hit directory switch a just like we did before you'll be able to see all the files with all of their attributes and you can see pretty quickly that our boot directory and our boot sector are missing they're missing because we deleted them and you know the reason why I deleted those two things is because they kind of Encompass everything that could possibly happen to leave an MBR system not booting so by fixing both of those missing files it should be able to fix most problems with an MBR boot so let's fix it okay so now that we're on the C drive we want to check the e Drive real quick because the E drive as we could see from disk part was the drive that it was probably our windows partition so when we go to eat and run a directory as you can see there's our Windows folder there's our user folders our program files and whatnot so this one we can be pretty confident that this is our Windows folder so from here we want to go back to the C drive and then from here the First Command that we want to create is we're just essentially going to recreate all the boot files that we deleted before so to do that we're going to type in BCD boot space and we want the path to our Windows folder now we know that's in the e Drive so it's going to be e prompt backslash windows and then from there we want to hit a space we want to hit switch capital S and then we want to specify what our boot partition is now in this case our boot partition is actually C while our windows partition is e so we want to make sure to specify that one right there so we're going to go ahead and write C prompt for that however keep in mind that if your boot files are located on the same partition as your windows directory you're going to have to change this command accordingly just make sure you specify these two things individually your windows directory the specific partition and folder that it's located in as well as the drive that all your boot files are on and then once you do that go ahead and hit enter it'll say boot files created successfully so if we hit run a directory now and obviously we have to do directory a because these are all hidden files you'll see that our boot folder and our boot manager are back the way they were however it still won't boot so we're still going to have to do a few things in order to get this thing to boot so the next command we're going to run is boot rack this is the one we talked about earlier and we're going to have the forward slash scan OS and all this is going to do is it's going to scan for Windows operating systems that it can find on the system and as you can see here it says total identified Windows installation zero now this is an error that you may come across and if you do it's really easy to fix all you got to do is hit CD boot and then from there the file that we're looking for is this one right here it's the BCD file and all this means is it through a generic BCD file in it that just isn't compatible with our MBR system so it's easy to fix all you're going to have to do is hit REM for rename and then type in BCD and then give it another name so I'm just going to call it BCD dot BK for back and that'll give you a backup copy of your BCD file so if we scroll up here you'll see that it just says backup now but we currently have no BCD file but that's okay let me show you how we can fix that so the next thing we do is we go back to our root directory here and we're going to run boot rack again but this time we're going to have forward slash fix MBR and then from there it will say operation completed successfully and then the next command we want to type is going to be fixed boot now this is the command that will fail if you're not using a 1703 or earlier ISO but when I hit enter you'll see the operation completed successfully if you get the error that says access denied then that means you're using too early of an ISO you're going to have to use an older ISO in that case now the next switch that we're going to run is still bootrec but this time we're going to type in rebuild vcd and now rebuild BCD because we deleted the BCD file before this is actually going to rebuild the BCD file based on our boot configuration that we're currently using so once I hit enter you'll see it's scanning all disk for Windows installations and if found one this time so we got e-windows and the reason it found it is because we deleted the BCD file before so all we're going to want to do is Click Click yes we do want to add these to our installation so hit yes and hit enter and it'll say the operation completed successfully now there's one more thing that we have to do we have to go back into disk part again so go back into disk part it takes a second to start once it does we go list disk and most of the stuff you may already know like we already know disk 0 is our boot drive so we're going to go select disk zero and then from there we have to do list volumes to see our volume now the volume we're looking for right now is not the windows volume but it might be it's a little complicated but what we want is we want to know which partition actually has our boot files on it we don't really care where the windows directory is we want to know where the boot sector is located and in this case we know it's on the C drive well if you don't have a 50 megabyte Reserve partition on your system then your boot files are probably going to be on the main partition and in that case that's going to be the one you're looking for we want to know specifically where our boot files are and in my case it's going to be on this 50 meg system reserve file so for there we're going to hit select volume 1 because volume one is our C drive which is our system reserve drive and then hit enter it'll say that the volume one is selected and if you want you can actually Hit List Vol to list volumes and you'll see a little star in the end there to tell you that that is the currently selected volume and then from there all you have to do is run one command active and what that's going to do is it's going to Mark the boot drive as active so the system knows which partition has all the boot files and then from that point we can hit exit and then go ahead and hit exit again in order to exit out of the command prompt now the next thing we need to do is reboot the system and hopefully it'll boot Windows let's find out so I'm going to go ahead and turn it off I'm going to pull the USB drive out of it and we're going to hit the power button and we're going to see if we boot into Windows if everything went the way that it's supposed to we should have fixed the MBR bootloader and gotten our Windows back but I don't know it could fail if it does fail I'll just have to film this entire section again but hopefully it won't so here we go there we go it's booting into Windows now once it gets there I'll go ahead and see you in Windows and we'll check to see if our text file is still sitting on the desktop okay so as you can see there's our text file if we open it up I guess we fixed it so as you can see it is possible to fix an MBR bootloader in fact when the tools are functioning correctly it's pretty easy now the biggest takeaway from this guide that I want you guys to remember is that this guide as I said at the very beginning of the video has to be done with a Windows 10 1703 or earlier ISO and you know another takeaway is that you should probably keep your old windows CDs because this one kind of saved my butt but now I have it on as an ISO I really don't need the CD anymore but it's really important to keep your old windows CDs for that reason specifically I mean the likelihood is that I'm never going to install 1703 again but you never know what you might need the iso for but you know what the next important thing that you guys need to pay attention to is what partition your boot files are located on it's really important to know the specific partition in order to follow this guide in the windows install that we used in this video we had a dedicated 50 megabyte partition at the beginning of the drive that contained all of our boot files and that's what you get when you have a fresh install of a newer build of Windows like 22 H2 that I used in this video however if your system was originally set up with an older build of Windows all of your boot files might be on the main partition and if that's the case you need to adjust the instructions from this guide according to what partition your boot files are on ultimately though if you're still running an MBR partition it might be a good idea to convert that partition to GPT that is of course if you're running a UEFI bios if that's the case you can always follow this guide here to do that conversion without losing your data just keep in mind that that video only works on a system with a UEFI bios if you try to follow it with a system with an older bios your system won't boot anymore but as always you guys have a great day

Channel: CyberCPU Tech

Views: 129,314

Keywords: fix mbr partition, fix master boot record, windows 10 wont boot, corrupted mbr, corrupted master boot record, master boot record, repair master boot record windows 10, windows 10

Id: EdgzHS7poIc

Length: 21min 17sec (1277 seconds)

Published: Mon Jun 05 2023