Photoview Render Error

When I start a photoview rendering of a motion study I get the following message a few minutes into the progress:

The process cannot access the file because another process has locked a portion of the file.

Anyone familiar with a message like this? Could it be graphics card related? Or memory space?

Any opinion will be much appreciated as I've never seen anything like this before and Google searching did not yield much.

Thanks

SolidworksMotion Studies