Just trying this… Identified 4417 files… Told it to rename everything over 400 days old… Does a few then appears to hang with not responding in title bar and spinning blue circle… Also brings the rest of the PC to its knees in this state… The PC is not a slouch at all with an i7-4771 quad core CPU and 16 GB of RAM.
I’ll let it run a bit and see if it eventually finishes them all.