[chirp_users] "Error Reading Data from Radio..."

Trying to download radio image fails with the following error:

“An error has occurred

Error reading data from radio: not the amount of data we want”

Radio is a BTECH UV-5X3. Using latest Chirp build (downloaded this morning). Running on Mac, 10.10.5 (Yosemite). Python runtime is installed. I don’t see anything relevant in the FAQ or in recent threads on the list. I tried resetting the radio to its defaults - no change, same error.

Any ideas?

Jeff