Safe to decrypt 1 TB Windows 7 Truecrypt system drive in XP?

[Calidore266]

I'm running Windows 7 on a 1 TB Truecrypt system-encrypted drive; no problems normally. However, this morning on bootup I got a fast flash of blue screen and a quick reboot. Trying safe mode doesn't work either.

So, I need to decrypt the drive before trying any repairs, but my old PC is still running XP. My question is, will XP play nice when I use that to decrypt a 1 TB Win 7 filesystem, or will it not be able to recognize/deal with the newer one and possibly create a bigger mess?

 

[Fardringle]

Is the drive formatted as NTFS? And do you have the encryption key?

 

[Calidore266]

Is the drive formatted as NTFS? And do you have the encryption key?

Hi, Fardringle. Yes, it is NTFS and I do have the encryption key. I'm not worried about the decryption process itself per se; Truecrypt itself has never given me any kind of problem on either system. I just don't want Windows XP to choke on a newer form of NTFS, for example.

 

[paul878]

I'm running Windows 7 on a 1 TB Truecrypt system-encrypted drive; no problems normally. However, this morning on bootup I got a fast flash of blue screen and a quick reboot. Trying safe mode doesn't work either.

So, I need to decrypt the drive before trying any repairs, but my old PC is still running XP. My question is, will XP play nice when I use that to decrypt a 1 TB Win 7 filesystem, or will it not be able to recognize/deal with the newer one and possibly create a bigger mess?

Why don't you just mount the TrueCrypt drive in XP and copy everything into another drive to be safe.

 

[Calidore266]

Why don't you just mount the TrueCrypt drive in XP and copy everything into another drive to be safe.

Hi, Paul878. I'd have to buy another drive, which is possible, but I'd rather avoid the expense at the moment. Then there's still the big question of whether Win XP will behave itself when confronted with Win 7's filesystem.

 

[Bubbaleone]

.....Then there's still the big question of whether Win XP will behave itself when confronted with Win 7's filesystem.

There is no difference between the XP and W7 file systems; they're both NTFS. The only thing you might encounter is XP not recognizing W7 SIDs (security descriptors) and trying to automatically run chkdsk on the W7 drive when you boot the XP machine. If chkdsk trys to run on the W7 volume when you first boot XP; you'll see the screen prompt to skip the disk check by "pressing any key". When you see that screen prompt you'll have 10 seconds to press any key and abort chkdsk and Xp will continue to boot to the desktop, then you can decrypt your W7 volume.


Edit: If the encrypted system drive has errors serious enough to prevent your W7 machine from booting either normally or in safe mode you're going to have to run chkdsk before you'll be able to access the drive, which poses a problem since chkdsk can't run without that drives encryption key. TrueCrypt will need to be installed on the XP machine in order to run chkdsk on the mounted W7 TruCrypt system drive:

What do I do when the encrypted filesystem on my TrueCrypt volume is corrupted?

File system within a TrueCrypt volume may become corrupted in the same way as any normal unencrypted file system. When that happens, you can use filesystem repair tools supplied with your operating system to fix it. In Windows, it is the 'chkdsk' tool. TrueCrypt provides an easy way to use this tool on a TrueCrypt volume: Right-click the mounted volume in the main TrueCrypt window (in the drive list) and from the context menu select 'Repair Filesystem'.

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[Calidore266]

Thanks for the responses, everyone. Here's where I'm at so far:

I ended up biting the bullet and getting a new portable drive to back up to. In addition to giving me a safety margin now, maybe it'll encourage better backup habits in the future.

Hopefully useful info: CHKDSK XP scanned the Win 7 disk with only one flag: "Correcting errors in the uppercase file." According to Microsoft's Knowledgebase, "This problem occurs because of the differences in the uppercase file between Windows Vista and the earlier versions of the Windows operating systems," and can be safely ignored, as it's not an actual problem with the file system. The rest of the checks, including security descriptors, went without a hiccup. Unfortunately, that means I still don't know what the problem is.

I then became hopeful that I'd found the problem early while backing up; the first folder I copied was Users, and my own local Temp folder had well over 65,000 *.tmp files from a program that apparently hadn't been cleaning up after itself. I deleted that mess and tried booting again, but still no go.

So now I'm copying everything over to the portable drive, and then I'll decrypt the drive and, for lack of a better idea, reinstall Windows. Since the drive shows as error-free, hopefully the reinstall will replace whatever startup file(s) somehow got hosed. Unless, of course, somebody here has a better idea. I'm still pretty new to Win 7, so please do tell me if I'm missing something.

 

[Bubbaleone]

That's good news about chkdsk only doing a bit of maintenance cleanup, and not finding any (significant) errors. This, as well as your description of the bluscreen and boot failure, suggests that the BCD (Boot Configuration Data) store may be corrupt, in which case you only need to access the Windows 7 recovery environment in order to repair it, rather than having to reinstall Windows. It might also be a driver conflict or perhaps a corrupt system file that's caused your system to crash, but repairing the BCD will eliminate it as a cause for crashing. The following link walks you through the procedure: How To Rebuild the BCD in Windows


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[Calidore266]

That's good news about chkdsk only doing a bit of maintenance cleanup, and not finding any (significant) errors. This, as well as your description of the bluscreen and boot failure, suggests that the BCD (Boot Configuration Data) store may be corrupt, in which case you only need to access the Windows 7 recovery environment in order to repair it, rather than having to reinstall Windows. It might also be a driver conflict or perhaps a corrupt system file that's caused your system to crash, but repairing the BCD will eliminate it as a cause for crashing. The following link walks you through the procedure: How To Rebuild the BCD in Windows .

Thanks much for the link, Bubbaleone; there's some useful info there. It even tells me what Win 7 was doing when it hosed my last encrypted system drive while installing to another drive. Also thanks for the info re. BCD. Hopefully I can avoid a reinstall.

I was disappointed to see that for some reason I don't get a couple of useful boot options--Enable Boot Logging and Disable Automatic Restart on System Failure. Both of those would have helped immensely, but they don't appear (along with some others) on my F8 screen.

Anyway, I finished the backup yesterday (Useful tip #2: Copying nearly a terabyte to a portable drive via USB2 can take a while) and am now decrypting the drive in question, as Win 7 has already shown the capability and willingness to inflict area-of-effect damage, and I don't want to give it a second shot at messing up an encrypted drive.

Unfortunately, while Truecrypt will allow you to manually mount a system-encrypted drive that's been plugged into another PC as a secondary drive, it will not remove the encryption that way. The drive has to still be a system drive and must be decrypted via the rescue disc, which doesn't allow you to still use your system like the in-Windows way does and is also MUCH slower. Math says mine will finish at around 3 a.m. Thursday, so then I'll finally get to try to fix the problem.

 

[Bubbaleone]

Are you referring to trying to access the WinRE repair tools, via the F8 key, on your Windows 7 drive that crashed? If so, it would be preferable to boot your Windows 7 installation disk, then select the repair tools option in the lower left corner of the Install Windows screen. You'll then have access to all the WinRE repair tools, including the command prompt used to repair the BCD.

 

[Calidore266]

Well, Murphy's Law may have made the whole thing moot. Some workmen picked this morning, almost exactly 24 hours into the decryption process, to suddenly cut off power. When I restarted after the power came back on, it went back to the beginning, meaning I can wait until Friday morning now, or I can just say "Screw it", reformat the bleeping drive, and reinstall Windows from scratch, which is the option I'm leaning toward. Anyone know if the double-install trick still works for a clean install of a Windows 7 upgrade, or should I just pre-install XP or Vista (got both)? I'd prefer doing a clean install if possible.

 

[Steltek]

Well, Murphy's Law may have made the whole thing moot. Some workmen picked this morning, almost exactly 24 hours into the decryption process, to suddenly cut off power. When I restarted after the power came back on, it went back to the beginning, meaning I can wait until Friday morning now, or I can just say "Screw it", reformat the bleeping drive, and reinstall Windows from scratch, which is the option I'm leaning toward. Anyone know if the double-install trick still works for a clean install of a Windows 7 upgrade, or should I just pre-install XP or Vista (got both)? I'd prefer doing a clean install if possible.

It still works - I just did it on a system last week.