I've seen that complaint before, but my recollection about how to deal with it is foggy. Since that method seems to be problematic, I used the following method, oulined by our respected contributor Peter:
if you follow the notes below, you can rebuild your SD card.
The link below will take you to a '.zip' file that you can download to your PC/Mac. When you download this file you can flash a microSD card and recover your BB1.
This information can be found on the Brennan website
'Home' --> 'Questions' --> 'BB1 Pages' --> 'BB1 User Guide' and scroll down to the very bottom of the page in item 'How to upgrade the SD card'
https://drive.google.com/file/d/1IK370GD7j4Hnb8hHFafoN7FNaytQu9wS/viewHere is a summary set of steps to rebuild the SD card.
1. Download & install 'balenaEtcher' onto your PC/Mac.
2. Download the '.zip' from the link above to your PC/Mac..
3. Start up 'balenaEtcher' application on PC/Mac.
4. Point 'balenaEtcher' to the 'BB1SD.zip' file that you downloaded from the link above. (DON'T unzip the file)
5. Click on 'balenaEtcher', folllow the directions and click on the 'Start' button.
It will take 'balenaEtcher' a few minutes to flash and verify the microSD card.
6. On your BB1 plug in the newly flashed microSD card.
7. Power up the BB1.
8. Check the software version which should show as 'BB1 Oct 14 2019'. (this date may have changed by now)
9. Reconnect to your WiFi router.
10. Run a 'Web Upgrade' to upgrade to the latest software from the Brennan website.
11. Reboot the BB1
12. Run a software version check - should now show 'BB1 Jul 21 2020' (or similar date). (it should now be the most recent version)
So from a bare SD card to full upgrade should take approximately 20 minutes to complete.
13. Plug the SD card back into your PC, and copy the backed up '/music' folder back to the SD card.
14. Fit the SD card back into the BB1 and run 'Scan disk'.