Dear Pondus,
Thanks a lot for your quick response!
I understand that it happens more often that Avast is not able to scan files, and that this is not necessarily a problem as it does not say anything yet about the file itself.
However, Avast never gave this response before when scanning (I regularly perform a complete system scan). Do you think this is because the file in question (StateRepository-Machine.srd-shm) is related to a Windows update or something like that and therefore new?
In addition, what also made me a bit concerned was the blog post about this file I found elsewhere, with the text copied here below. Does anyone know what kind of file this is, and if it is really innocent? How can I know that its not a problematic file?
http://www.wilderssecurity.com/threads/hitman-pro-support-and-discussion-thread.236732/page-273:
"Suspicious files ____________________________________________________________
C:\ProgramData\Microsoft\Windows\AppRepository\StateRepository-Machine.srd-shm
Size . . . . . . . : 32.768 bytes
Age . . . . . . . : 26.1 days (2015-09-10 12:18:50)
Entropy . . . . . : 6.2
SHA-256 . . . . . : A482BAA7ADDC525DEA1A1EC46EF619F66CA3F02B87162BE2B99E181088C2A7C3
Fuzzy . . . . . . : 56.0
The file is hidden from Windows API. This is typical for malware.
The file is completely hidden from view and most antivirus products. It may belong to a rootkit.
The file name extension of this program is not common.
Program is running but currently exposes no human-computer interface (GUI).
Authors name is missing in version info. This is not common to most programs.
Version control is missing. This file is probably created by an individual. This is not typical for most programs.
The file is in use by one or more active processes.
The file is a device driver. Device drivers run as trusted (highly privileged) code.
Forensic Cluster
-1.2s C:\ProgramData\Microsoft\Crypto\RSA\S-1-5-18\d2abe790c186609ce700d6af614dbda9_a3d6c6f9-8be7-4367-b352-d22eca12c24f
-0.1s C:\ProgramData\Microsoft\Windows\AppRepository\StateRepository-Machine.srd-wal
0.0s C:\ProgramData\Microsoft\Windows\AppRepository\StateRepository-Machine.srd-shm "