Registry permission issue HKEY_CLASSES_ROOT Access denied

Hi everyone,

I have a nasty permissions issue when writing the the Windows Registry.

1. How did I noticed it?
When installing Adobe products, they end in Error 160: Access denied writing to the registry to a specific key (HKEY_CLASSES_ROOT aka. HKEY_LOCAL_MACHINE/SOFTWARE/Classes)

Code:

WARN: Error Setting Registry - Start 64-bit:1 root:0 key:.icap name:Default type:REG_SZ data:InCopy.Markup.Assignment Package. Check for Registry permissions. (Error: Error 5 Access is denied.)

2. How do I reproduce?

I have Windows 10 20H2. I tried to use the command prompt reg command to simulate what Adobe is doing based on the log above and have the same outcome. Which means this is really a permission issue here.

Code:

C:\WINDOWS\system32>reg add hklm\software\classes\.icap
The operation completed successfully.

C:\WINDOWS\system32>reg delete hklm\software\classes\.icap

Permanently delete the registry key HKEY_LOCAL_MACHINE\software\classes\.icap (Yes/No)? y
ERROR: Access is denied.

On other PCs running Windows 7 or Windows 10 2004 The operation succeedes. No issues.

Interestingly enough, if I use regedit.exe to perform the SAME operation, it succeedes in both creating, deleting, or changing the default value. Both are ran as Administrator.

3. What did I try to fix?
I tried setting permissions manually for all users on the HKEY_LOCAL_MACHINE/SOFTWARE/Classes key and/or HKEY_CLASSES_ROOT but the same issue occurs.
I tried using tweaking.com Windows Repair to reset all permissions, but it doesn't seem to help either.

Any suggestions are very welcome.

Thanks,
Mihai

So you can create but you can't delete same register just created.
You have permission to create but not to delete using reg, but using regedit you can do both.

Did you ran the antivirus? (maybe a software forbids the deleting)
Does the antivirus has some register protection?
Did you try the same reg create and deleting under a safe boot?

So, further investigation:
1. Using regedit: can create, can modify, can delete
2. Using reg: can create, can modify, cannot delete
3. Using Registry Workshop: cannot create, cannot modify, cannot delete.

I believe that the Adobe Installer experiences the same behaviour as #3, because it fails at registry creation/modification.

What is even stranger, using #3, I can rename, modify or delete EXISTING keys (under HKLM/Software/Classes), but cannot create a new key or edit a newly created key (that was created in steps #1 and #2 by rededit and reg).

I have ESET Internet Security installed, tuned off for this test.

Just for the sake of it, I tried creating another key with a different name and surprisingly, it works. It seems that only the key named ".icap" (or containing icap in the name, I tried .icap123 with the same behaviour) has this issue... Isn't this very weird? I cannot understand this behaviour.
If I delete the key with regedit, the permissions should be reset when created again...

dalchina said:

This appears to address this issue- not sure if it adds to what you've tried.

dalchina said:

Fix error code 160 while installing Creative Cloud apps on Windows
Solved: Error 160 - Adobe Support Community - 9295845

This seems a known Adobe product-related problem, so I suggest best referred to an Adobe forum rather than as a general O/S issue.

This seems not to be an Adobe issue, as I can reproduce it without using any adobe product... And the Adobe forums they say also somthing about wrong permissions.

Megahertz said:

So you can create but you can't delete same register just created.
You have permission to create but not to delete using reg, but using regedit you can do both.

Did you ran the antivirus? (maybe a software forbids the deleting)
Does the antivirus has some register protection?
Did you try the same reg create and deleting under a safe boot?

I have now rebooted into safe mode, and the key deletion now works properly. You may be right, some kind of software blocks somehow the access to specific keys. Any clue what can I do to identify the culprit here?

My first bet would be the antivirus and second a resident app (start with windows), maybe even a Adobe app.
Try MSConfig clean boot. If it does work, enable half. If it work it's on the other half. If it doesn't it's on the half you enabled.
Go enabling till you find the bad guy.

Megahertz said:

My first bet would be the antivirus and second a resident app (start with windows), maybe even a Adobe app.
Try MSConfig clean boot. If it does work, enable half. If it work it's on the other half. If it doesn't it's on the half you enabled.
Go enabling till you find the bad guy.

I found the culprit here. It seems the Acronis True Image Home 2021 has a protection service that blocks the access to this specific key. Weirdly enough, I don't know why this .icap key only is blocked and also If I turn off the protection it still blocks the access. Only if I disable the Acronis services and restart the PC it stops blocking...

Glad you found it.

Please mark this thread as solved.