Hi All, hope you're well. My first subscription here, I see it's quite a busy forum so I'm sure I'll find interesting thing to discuss.
The main reason I'm here today is because I have an annoying problem:

I'm accessing my network files hosted on a Synology via windows explorer (unc path &/or mapped drive). Since a few days now, I'm unable to open any file as I get the following messages:
Picture: "it looks like you don't have permission to view this file. Check the permissions and try again.
Any other file : "The directory name is invalid."
Open with other program than Windows one also mention permission issue.

Here's what I tried:
Diskcleanup, SFC /Scannow (clean), chkdsk /f /r (clean), Delete all network drives & windows credential for this network, killing all tasks, safe boot, disabling WinDefender, Firewall...

I'm currently using b16251 of W10x64. I had this problem twice with older versions of W10 and the only solution I found at the time was to format and reinstall windows as I'm completely handicapped in this situation.
I can access properly all files of that network on other computer using W10 & W7 so it's definitely linked to this setup.
Not sure it's related to insider preview as I had this problem on Creator Update 1703 and upgraded to preview thinking it will solve the problem...

Can anybody help me fix this please ? Thanks a lot!