Hello bs, thanks for the reply.
2. Can you send screenshot of the error report (Access to memory location is invalid).
I got exactly same message as RejZoR posted when I had this login issue although I use Windows 7 not 10.
My former translation of the error message is just not good, it should be "Invalid access to memory location".
I attached an error message I get when I try to run Windows Update with maximum HIPS level.
No reboot is required, just change the settings and get this. Revert it and I can run WU without issue.
1. Can you, please, try to rename guard32.dll (C:\Windows\SysWOW64\guard32.dll). Maybe you have to do it in safe mode. Does it help?
I just did that and renaming guard32.dll does not affect the symptom at all.
Just a note, my issue is changed a bit.
Now, I can login to Windows but got a black screen only with mouse-cursor.
Ctrl+Alt+Del does not work with error message saying it failed to open the screen.
I successfully made kernel dump with and without guard32.dll (renamed or not) during black screen.
Dumps were uploaded to avast FTP:
NON_kernel_dump_without_guard32.7z
NON_kernel_dump_with_guard32.7z