Recently I took a look at Avira AntiVir 10 (Personal and Premium). In that post, I had briefly mentioned a new service called avshadow.exe. I have noticed that many users have been baffled by this new service (its shadowy name isn’t perhaps the most comforting). Anyway, as mentioned in my earlier post, AvShadow is Avira’s own enhanced implementation of the Shadow Copy feature present in Windows Vista and 7.
However, what does an antivirus product have to do with Shadow Copy? The answer was provided by an Avira GmbH employee in the public forums.
This process (avshadow.exe) is our implementation of the Shadow Copy Service
(something offered by current Windows Versions). It is used to scan
files that are locked or in use by creating a “shadow copy” of the file,
which:a) allows us to scan it and
b) does not interfere with any processes continuing to modify the “original” file.
So there you go. Now you know why avshadow.exe is required.