Root mapped network drive refresh "each" access with explorer

Hello,

We encounter a problem with our new Windows 2012 R2 file server (deduplication is enable on it).

Our mapped network drive on windows 7, "refresh" the root directory list when we access it. The refresh appear again few seconds after, when we browse the directory and return to the root. It's like a timeout.

We looked into several solution like:

1. Registry keys about DirectoryCacheLifetime,FileNotFoundCacheLifetime andFileInfoCacheLifetime was set to 0 in a previous GPO to solve the problem of showing new file. These parameters were reset to their default value -> problem still occur.
2. Disable SMB3 on server side to SMB1 -> problem still occur.
3. Previously, a GPO use to change the internet explorer settings about Check for newer versions of stored pages was set to Every visit to the page.I know that IE parameters can affect browser settings so I restored this parameter to it's default valueAutomatically -> no change.

Thx for your help.