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Windows 7: Need to edit registry on non-booting Windows 7 installation

04 Jul 2010   #11

Windows 10 Pro x64 x3, Ubuntu

As an alternative there is the old shool method

You may have to physically move the HDD to another working system If you do not have a dual boot option on the original system or access to a live CD for the copying stages
  • Boot the other computer with a boot diskette or dual-boot OS and then copy the problem hive file to a removable media or directly across the network to your system.
  • Log in as administrator on your system and run REGEDIT.EXE.
  • In the Registry Editor, select either the HKEY_LOCAL_MACHINE or HKEY_USERS window, and then choose Registry | Load Hive.
  • Locate the file copied to the system in step 1, select the file, and click Open. This loads the hive into the local registry as a subkey of the selected key.
  • Make the necessary changes to the damaged hive and then choose Registry | Unload Hive.
  • Copy the hive file back to its original location on the problem computer. Restart to test the system.

My System SpecsSystem Spec
04 Jul 2010   #12

Windows 7 Ultimate

Thanks for all the replies so far. Heres an update of where I am :

The machine has 2 hard disks - disk 1 (80Gb solid state) which has 2 partitions - 100Mb system reserved and the remaining partition with the original Win 7 installation on it. Disk 2 is a 1.5Tb Serial ATA.

I've installed Windows 7 to the second disk, after doing so disk 1 does not get drive letters assigned. Gone into drive management and I can assign a drive letter to the 100Mb partition but not the larger Win 7 partition.

If I put the Windows 7 DVD in - and ask it to install to the partition on disk 1 originally containing Windows 7 - it says it cannot install to this drive as its an unknown partition type.

Loading the original Windows 7 installation does the same as before - ie in safe mode it will load a pile of drivers and then hang at the message of "Loading \Windows\SysWow64\CTMMount.sys".

The problem originally occurred after installing Comodo Time Machine.

I'm at the stage now where I just need access to this original drive so that I can copy the contents of the Users folder somewhere else - at this point I will be happy to delete and recreate the partition and reinstall Windows 7.

Anyone got any further ideas/suggestions?


My System SpecsSystem Spec
04 Jul 2010   #13
Microsoft MVP

Windows 7 Ultimate 32bit SP1

This 'service' is located here:


COMODO Internet Security"="c:\program files\COMODO\COMODO Internet Security\cfp.exe

I have read that there is an "uninstall" in CTMMOUNT.sys
My System SpecsSystem Spec

04 Jul 2010   #14

Windows 7 Ultimate
Issue resolved

Problem solved!

I ran testdisk - used this to firstly copy the files off the partition that windows couldnt access and then used it to re-write the MBR for that disk.

Disk then appeared correctly in the second windows installation.

Removed ctmmount.sys - rebooted the original windows installation - all works fine!

Thanks for all your help!
My System SpecsSystem Spec
04 Jul 2010   #15
Microsoft MVP

Windows 7 Ultimate 32bit SP1

Thanks for reporting back!
My System SpecsSystem Spec

 Need to edit registry on non-booting Windows 7 installation

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