Dual Boot issues (Win7/10) and data corruption

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  1. Posts : 6
    Windows 7

    Dual Boot issues (Win7/10) and data corruption

    I have a major problem and I'm hoping someone can help me figure out how to resolve it.

    Here's my environment:
    - I have Win7 installed on Drive 0 on a single partition (SSD); except for 100MB "system reserved" partition
    - I have Win10 installed on Drive 1, which has 3 primary partitions and 3 logical drives (see screenshot)

    Win7 was installed originally. When I installed Win10, I unplugged the SSD so that only Drive1 was visible during Win10 installation. Win7 is my primary OS, when I want to run Win10, I change the boot drive using BIOS boot manager (ie. pressing F12)

    Here's the problem:
    In most cases, after returning from Win10 back to Win7, Win7 would tell me that the disks need to be verified (chkdsk). This would finish relatively quickly and wouldn't usually find any errors. Until last night, when it found/repaired a slew of errors and the result was locked files/folders (security descriptors had to be reset) and a lot of corrupted files.

    I should also mention that when I was in Win10 last night, there were some very strange things occurring:
    - Firefox wouldn't start; just no response at all. Once I got back into Win7, trying to start Firefox told me there were corrupted files.
    - Perhaps the strangest detail: in certain folders, I noticed that the files in the folders seemed to be a reflection of the contents from a couple weeks ago (most likely, the last time I was in Win10). There were files displayed that I had since deleted, and there were missing files. Once I got back into Win7, the file lists were back to normal.
    - There was a Windows Update which failed to install. This was before I was completely convinced there was a serious problem, so I rebooted back into Win10. Win10 failed to load. That was the least of my concerns.

    Another possibly relevant detail: I'm fairly certain that no files on my disk0 were affected/corrupted -- only files that are on the same physical disk as Win10.

    I also remember having a heck of a time setting up the partitions on Disk1 and that was before installing Win10. I don't remember the exact details, but I think I was getting errors/corruption and it only "worked" once I used 6 partitions instead of the 7 that I wanted (or maybe I fiddled around with the type of partitions).

    Because I suspect the problem has to do with the way that I'm dual-booting, I've attached a screenshot of my disk management. I've read that the 100MB "system reserved" partition is normal for Win7, but that Win10 needs a 350MB reserved partition, but there isn't one. It seems unlikely that it's sharing Win7's since that drive was disconnected when I installed Win10. Is that the problem? Why didn't Win10 create a system reserved partition -- do I have too many partitions on that disk?

    I have no problem wiping out the Win10 partition, but the other partitions on the disk could be a problem, so any possible solutions that might require formatting/losing those would be more of a last resort.

    Thanks for any help!
    Attached Thumbnails Attached Thumbnails Dual Boot issues (Win7/10) and data corruption-diskmanagement.png  
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  2. Posts : 9,788
    Mac OS Catalina

    Dual boot with 7 & 10 has been problematic. Hang tight and one of the others who is more knowledgeable on making it work correctly.
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  3. Posts : 4,782
    Windows 11 Pro 64 Bit 22H2

    I should also mention that when I was in Win10 last night, there were some very strange things occurring:....no files on my disk0 were affected/corrupted -- only files that are on the same physical disk as Win10.
    Your Drive 1 HDD may have Bad Sectors leading to corrupted files.
    In Windows go to Start/Search and type CMD, Right click the CMD results and Run As Administrator. In the Elevated Command Prompt type the drive letter of the Windows 10 drive (ie) D: or whatever, and press enter. (ie) D:\> at this prompt type chkdsk /R and press enter. If in Windows 7, type a Y for Yes to Unmount the drive, if you are in Windows 10 then type a Y for Yes and reboot the computer. Check Disk will go through 5 stages and will take a long time. Check Disk will check for bad sectors and try to move the files to a good sector near by. If there are too many bad sectors, Check Disk will hang or fail. The drive will need to be replaced.
    For a second opinion, in Windows 7, you can download Seatools for Windows. And run this on the Windows 10 drive. Run the Short and Long diagnostic tests. The long test checks for bad sectors and will take a long time. If either test fails, the HDD needs to be replaced.
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  4. Posts : 6
    Windows 7
    Thread Starter

    Thanks for the replies.

    I'm in the process of running chkdsk /r now -- I'll run it on all 6 partitions.

    Well, I'm checking the Win10 partition (W:) and it is finding a lot of "bad clusters." I expected there to be problems since Win10 wouldn't even load, but do "bad clusters" indicate a physical problem?

    Ok, the scan of W: is now complete, and to answer my own question, I presume that "bad clusters" are NOT a physical problem ("0KB bad sectors"). Here's the summary:

    CHKDSK discovered free space marked as allocated in the
    master file table (MFT) bitmap.
    CHKDSK discovered free space marked as allocated in the volume bitmap.
    Windows has made corrections to the file system.
     122879999 KB total disk space.
      26458040 KB in 96774 files.
         84996 KB in 23263 indexes.
             0 KB in bad sectors.
        254427 KB in use by the system.
         65536 KB occupied by the log file.
      96082536 KB available on disk.
          4096 bytes in each allocation unit.
      30719999 total allocation units on disk.
      24020634 allocation units available on disk.

    I have the entire log if you'd think it'd be helpful, but otherwise, the only errors I saw were about 40 cases of moving bad clusters, e.g.
    Windows replaced bad clusters in file 282
    of name \Windows\Logs\CBS\CBS.log.

    I'll run chkdsk on the other partitions, but the *only* time Windows decides it needs to run an unsolicited chkdsk is after I've booted into Win10 (ie. nothing when I go into Win10, but chkdsk *will* occur when I boot back into win7). On my regular, daily boot into Win7, there are never any problems; I rarely boot into Win10 and it's only after I've done so that the chkdsk occurs. So it doesn't really seem like a physical problem.
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  5. Posts : 9,788
    Mac OS Catalina

    That moving of data in that cluster, could just have been a potential problem, maybe not. SSD's have a habit with Windows thinking that there is a issue, when there actually is not. You can use a Linux Live DVD and run S.M.A.R.T. Tools to see what is going on. SeaTools will not work with SSD's, since it is targeted more towards Platter drives.
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  6. Posts : 72
    WIndows 10 Pro x64

    Disable fast startup in windows 10 (control panel - power - choose what the power button does in the left hand side & then click change settings that are currently unavailable then untick fast startup) This has been a well known issue with dual boot systems, windows 10 locks the drives if fast startup is enabled so when you reboot into windows 7 it prompts you to run chkdsk.
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  7. Posts : 6
    Windows 7
    Thread Starter

    bro67 -- The chkdsk's all completed without any bad sectors. Ironically, I had to reinstall VirtualBox after the chkdsk found and repaired some bad clusters on that partition, even though I had run it without problems earlier that morning. Just the Win7 drive is an SSD and not the Win10 drive. I did do a scandisk on the SSD, just to make sure and it did find a few orphaned files.

    Banzi -- thanks for the tip about disabling fast boot. That does sound promising. I'm a little gun-shy to even try booting into Win10 at the moment, but when I do, I'm expecting to have to re-install it. I've almost finished verifying that all the files are restored and I'm also planning on doing temporary backups of most everything before I try win10 again.

    On the other hand, I'm also considering that this may be a sign that I should just cut ties with Win7 and transition to Win10 full-time. But for Media Center I would have switched a long time ago...
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  8. Posts : 18,432
    Windows 11 Pro

    EsJeff said:
    But for Media Center I would have switched a long time ago...
    Kodi is a great replacement for Media Center:
    Kodi | Open Source Home Theater Software
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  9. Posts : 2,799
    Linux Mint 20.1 Win10Prox64

    Looking at your system specs. You do have a pretty good system and UEFI support:
    Gigabyte GZ-z97X-Gaming 3, i7 4970K......

    Your Disk 0 looks OK with Windows 7 installed using MBR partition scheme.
    However, your Disk 1 does not look standard with Windows 10 installed also using MBR partition scheme and might get confused with Windows 7 when boot up.

    Normally for Windows 10 installation, you'd would get 500MB (not 350M as you said above, it's true for Windows 8) System Reserved Partition and C drive.

    Since your Disk 1 was initialized as MBR disk, that would limit the # of primary partitions to 4 so drives: F, H, I became logical drives.

    Here's my suggestion:
    1. Download and install: MiniTool Partition Wizard with Window 7 running. Run and right click on Disk 1 ( Minitool show it as Disk 2) then select convert to GPT disk.
    2. Right click on Windows 10 drive and delete this partition then click Apply to commit the changes of step 1 & 2. Might take a while to complete converting 1TB HD.
    3. Disconnect Disk 0 and boot up Windows installation Media with UEFI Mode selected.
    4. Select Custom->Hi Lite the unallocated partition (do not format) then click Next to install Windows 10.
    5. Once done, you'd get 4 partitions:
      450MB Recovery
      100MB EFI System
      16MB MSR
      C drive
      F,H,I will become Primary partitions.
    6. Reconnect Disk 0 (Win 7)
    7. Use F12 to select which Windows to boot from.

    NOTE: Make sure in BIOS you have "Boot Mode Selection set to both "UEFI and Legacy"

    Here's how I set up my Windows 7 on disk 1 & 10 on disk 0.
    Dual Boot issues (Win7/10) and data corruption-.jpg

    On the other hand, I'm also considering that this may be a sign that I should just cut ties with Win7 and transition to Win10 full-time. But for Media Center I would have switched a long time ago...
    Windows Media Center in Windows 10:
    Here is how to install Media Center on Windows 10

    Dual Boot issues (Win7/10) and data corruption-.jpg
    Last edited by topgundcp; 24 Jul 2016 at 18:19.
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  10. Posts : 6
    Windows 7
    Thread Starter

    Thanks, topgundcp! I will definitely be following that advice, once I back everything up. You didn't mention it, so I assume that the conversion to GPT won't have data loss, but I'm just a little paranoid when messing with partitions (bad experience with Partition Magic.....).

    Also, thanks for the tip about WMC! I never came across that and all my research was Kodi, Kodi, Kodi. So, about a month ago, I installed Win10, MediaPortal2 and Kodi on my laptop which serves as a PVR (the primary functionality I need). I can't say it was easy, but I did get it running successfully. I'm just not as happy with it compared to WMC.
      My Computer


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