[chirp_users] GT-3TP, suddenly cannot connect to radios, W10 v1903

For months, I've been successfully cloning GT-3TPs for our own use and UV5Rs for friends. Suddenly, last week, I can't connect to any radios via CHIRP. I've installed the most recent CHIRP versions. Today it's chirp-daily-20210520-installer.exe

I have two known good cloning cables that worked previously. Same results. I'm using BF-F8HP type as always. I've tried two different COM ports, CHIRP sees both.

The first time I tried this morning, Upload to Radio keyed the trx on the HT, solid carrier until I turned the HT off. That's a clue to me that something odd is up.

My next step is to install CHIRP on a different laptop and try there. Anybody BTDT?

Reno in Texas Quis custodiet ipsos custodes?