Question : Does Shadow Copy lock files during the scheduled task?

We currently have a scheduled task that runs Shadow copy service twice a day, 7am and 12pm on the main production file server. Users are reporting various random "Can't read file" errors for around 20 minutes after the scheduled task has kicked off.

Errors range from "Disk Is Full" to "Access Denied" and come from a varity of different applications including Windows Explorer. All of them are trying to access files on this server. I've checked file permissions and disk space but I am convinced that it has something to do with Shadow Copy.

Can anyone offer any advice?

Answer : Does Shadow Copy lock files during the scheduled task?

According to Microsoft's documentation on how shadow copy works, files are briefly unavailable for write access while the copies are being made, but they should always be available for reading:  http://technet2.microsoft.com/windowsserver/en/library/2b0d2457-b7d8-42c3-b6c9-59c145b7765f1033.mspx?mfr=true

How Shadow Copies Are Created

5.
The Volume Shadow Copy Service tells the writers to quiesce their data and temporarily freeze requestor (application) I/O write requests (I/O read requests are still possible) for the several seconds required to create the shadow copy of the volume or volumes. The application freeze is not allowed to take longer than 60 seconds. The Volume Shadow Copy Service flushes the file system buffer and then freezes the file system, which ensures that file system metadata is written and that the data is written in a consistent order.