Mine has just done the exact same thing on one of my machines, it was the main source that serves my media across the network.
All the data is still there, but I had to create a new Identity when it opened up.
Luckily I have all the KEYS backed up to a TXT file on the machine so having to go through and recreate R/W links on top of the full folders. As you can imagine 10GB of files to be re-indexed is not going to be quick.
Machine that lost ID is running Win7-64-ULT, my machines running Win7-64-HomePrem, Win10-64-Pro, and Win10-64-Home are OK if that helps.