We are currently experiencing an intermittent issue on our network.
We have a file server (Windows 2012 R2) at our datacenter with several shared folders. It has "Application Server" and "File and Storage service" roles installed.
A VPN is created between location A and the datacenter. Both routers are Sonicwalls (NSA240 and TZ600 respectively)
At location A, user A and B both have a network drive pointing to the same shared folder containing several Excel files.
Most of the times, user A access an Excel file, and when user B tries to open the file, he gets blocked because A is already editing the file. Which is the expected behaviour.
But sometimes, user A access the file, works in it, and meanwhile user B acces the same file, doesn't get any "already in use" warning, works in it, save the file. Then when A tries to save his changes, it says the file is locked by "another user".
User A was the first to open the file.
As a workaround for now, I've asked my users to save their file as soon as it's opened. I was never able to reproduce the problem that way.
Thanks in advance for all your help