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ERROR: Windows "cannot load classes registry file"

A

abro89

Contributor
Joined
Jan 14, 2014
Posts
77
Location
Vernon, VT
hi and hello:

SUMMARY:
I decided to remove MALWAREBYTES and after use of REVO Uninstaller I went into the registry for additional deletions. I became too aggressive and stupid me, DID NOT make a copy of the registry....(felt very confident...dah!!!).

PROBLEM:
Laptop operation is now "no recovery from SLEEP mode after depressing PWR button" to resume WINDOWS. Laptop state is "black screen and HD LED full on", totally locked up and PWR OFF/ON button is depressed to recover WINDOWS and WINDOWS Log-ON screen. After laptop boot, Windows displays options and "Windows Start Normally". After selection, Windows loads and I Log-On. Operation is OK again after this recovery method.

EVENT LOG:
Windows Logs>Application> Event Log shows error: "windows cannot load classes registry file". My OS is W7E-64b on Dell laptop with MS key (genuine).

IMPORTANT:
SFC /scannow shows NO ERRORS, DISM with /scanhealth shows NO ERRORS. I cannot open "Backup and Restore" in Maintenance folder so I think my issue is related to a possible corrupt user account profile.

QUESTION:
How can I recover in the Registry hivelist the needed registry file? File is absent in the registry, and is as follows:

hklm\system\currentcontrolset\control\hivelist. Other files are in tact but the _classes file is missing.

Thx in advance. You have helped me in the past w/ my non WINDOWS update issues and misc (dumb) icons missing issues.

Thx. Love SYSNATIVE Forums and staff w/ outstanding skills. You guys are the best.
 
Thx for the response. Good idea. Will try today.

I cannot launch Maintenance>Backup and Restore from the START>Programs list. The Control Panel and access to Backup and Restore may work as an alternative or I will use Start-Up repair w/ external W7E-64b DVD. I will investigate today after I make image.

Can I take the HD and connect externally to another laptop w/ same user acct setup and import the _classes subkey? Seems this is the fastest and easiest way.

Thx again..
 
The configuration is probably not the exact same, hence why the Windows Update team never allow someone to use the same fix script on different machines, despite the corruption appearing to be the same. The best option would to be either attempt a repair install using the installation media or attempt to revert back using the last known good configuration option.
 
thx...in other words I have two choices:

1. use a previous restore point as you suggested

2. use a repair install that reloads w7E-64b and keeps all my data and apps. However current up-to-date "updates" are lost so I would have to download all updates again (a real pain!!!!).

Will make a back-up of the HD and attempt to import/merge the good _classes file from a laptop having the same account name into the corrupt hivelist missing the _classes sub key (file).

thx...will let you know the outcome in a few days.
 
I'll step on my soapbox now.
Learn to create images.
I make images about every 2 months now for our four Windows 7 computers on portable external hard drives. That has saved me lots of times. When something goes wrong either through user error or a bad update/patch, it takes less than an hour to restore the newest image and do a few updates, mainly browsers and security programs and I am back in business.
 
Windows Vista/ 7/8/8.1 keep a regular backup of the registry handy in case you need to overwrite a corrupted registry. By default, the RegIdleBackup task runs every 10 days, so that’s as far back as you would lose if you replaced the current registry with the automatically backed-up files. You can find the backed-up registry files in \Windows\System32\config\RegBack folder.


Please boot your computer with Windows Setup Media and from Windows Recovery Environment start the Command Prompt.

Please type below command into Command Prompt and press Enter key.

Code: 
 Dir C:\Windows\System32\config\RegBack


Above command will list files stored within RegBack folder and there file size, make sure files are not zero size if they are do not follow below instructions.

akBT8zC.png


Please replace partition letter C: with Windows installed partition letter. When computer boots into Windows Recovery Environment (WinRE) environment the drive letter assign to Windows partition may not be C: drive letter because Windows 7, 8 , 8.1 and 10 creates a separate system partition when it's installed from scratch. The system partition contains boot files WinRE assigns the system partition the C: drive letter and the Windows installed partition will be assign any other drive letter usually D: drive letter is assign to Windows installed partition. The Bcdedit | find "osdevice" command can be use to find out the drive letter of the Windows installed partition the output of the Bcdedit command is similar to this osdevice partition=D:. The drive letter after partition= is the drive letter of the Windows partition.

Please type below commands into Command Prompt and for each command you have typed press Enter key.



Code: 
Replace C:\Windows\System32\Config\RegBack\*     C:\Windows\System32\Config

As files are replaced, the Command Prompt displays their filenames on the screen.

This procedure assumes that Windows Vista/7/8/8.1/10 is installed to the C:\ partition. Make sure to replace C:\ drive letter to the appropriate Windows OS installed partition drive letter if it is a different location.


Above commands renames the registry files at their existing location, and then copies the registry files from the RegBack folder to the C:\Windows\System32\Config folder.
 
wow...love it.

I will try and report back. I knew there had to be a method for recovery of the hivelist subkey. The fact that I am using the local registry backup voids potential user acct differences from a registry imported from an externaal laptop and registry.

Question: what book/publication/tutorial can you suggest for learning more about the registry?? Lots of stuff on the web and commands dont always work. I started a MS Sys Engineer cert many years but decided CISCO was the way to go. I lucked out.

Many thx again. Be safe
 
one question...I don't see the hklm_users hive in the regbackup list. Am i missing something?

I felt confident with your rsolution but realized the other keys in the backup directory I already have. What I need is the hivelist subkey in the hklm_user hive.

The hklm_users hive contains standard subkeys for user accounts plus hivelist. My laptop is single user so pretty easy to find subkey is missing. This also produces an error msg in the Windows logs.

Seems I am back to importing hivelist from another laptop with same user acct.

Perhaps the hivelist will be automatically generated from the other keys in the backup list???

Thoughts??? Ideas???
 
abro89 said:
Seems I am back to importing hivelist from another laptop with same user acct.
Click to expand...
This will not work, you can create the same username on two different machines but this is not the same user, every user have a different SID...

If you open the Command Prompt and type:
Code: 
dir /A "%localappdata%\Microsoft\Windows\usrclass.dat"

the file usrclass.dat exists or is missing?
 
User registry hive store within user profile folder (Users\UserName) its name NtUser.dat which contains your user profile settings.

If you have restore points you can use it to system restore Windows OS. You can also use tool like ShadowExplorer to browse restore points.

ShadowExplorer.com - Downloads
 
using cmd above with quotes displays "The system cannot find the file specified"

However file is found at:

users\<acctname>\appdata\local\microsoft\windows\usrclass.dat

thx for the recommendation NOT to use remote registry for hivelist import. I forgot about the SID properties. Will proceed with trying the import of the registry backups. I have made a HD image w/ Clonezilla. This is a good experiment

Dont want to waste your time. Will get the Amazon books that you recommended. Next easiest way to recover _hivelist is file transfer using laplink (or equivalent) and transfer all data and reload apps to another laptop w/ different username. This will be done in April.
 
abro89 said:
using cmd above with quotes displays "The system cannot find the file specified"

However file is found at:

users\<acctname>\appdata\local\microsoft\windows\usrclass.dat
Click to expand...

Do you have another user account on the machine? if not create one with Administrator privileges.

Using the new account locate the file usrclass.dat from the problematic account zip it and attach the zip file to your post please.
 
hi and hello again:

Your questions are answered below. Very funky operation with new acct added:

(a) could not find usrclass.dat file for problem acct. I determined there was no AppData file...dah!!!
(b)new account created w/ Admin acct ran very slowly...dah!!!
(c)could not create desktop icons and no populated list of Win features in START..dah!!
(c)Control Panel> adjust settings would not allow small small icons...dah..!!!
(d)abandoned pursuing solution for userclass.dat file
(e)my DISM only has option for /scanhealth. Where is /checkhealth and /restorehealth??

Next i used Tweaking.con (free tool) and launched full repair. Results fixed random BSD from video driver however updates were deleted...why??

Update are working but no IMPORTANT updates downloaded...why?? Will run SURT and all tools from Sysnative today to recover deleted updates

I am going to reload W7E-64b w/ key. I believe my current user profile is corrupt.

Thx for your help. Lets keep this thread OPEN until I reload.

Be safe.
 
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