Woke up this morning to find my pc had updated itself overnight.

I wasnt expecting that. No warnings.

Anyway, just like last time, I can no longer access shared folders on my server.

Also it bizarrely says in the bottom right corner : 

"Windows 10 Insider Preview - Evaluation copy. Build 14295.rs1_release.160318-1628"

In winver is says "Evaluation copy. Expires 16/7/2016"

Have I lost my free licence?

Bad Microsoft. Any major updates like this really should wait for user approval before installing.