External hard drive format changed overnight!
I copied a whole load of image files onto an external hard drive that has only ever been used with a Mac, the other day. Then, yesterday, I relocated about 20,000 Aperture previews from a legacy library onto the drive (in preparation for losing Aperture with Catalina)
I left it running overnight and noticed in the morning I had the 'disk not ejected properly message', and the external drive had de-mounted.
However, it now won't mount again and Disk Utility says it can't do First Aid on it or Mount it either. The drive itself is shown as mounted and First Aid shows no problems, but the Volume can't be either mounted or repaired.
I then noticed it says the 'Volume' is formatted as MS-DOS (32 Bit)!!! As I say, this drive has never been used on a Windows PC as far as I can recall, so how can this have happened?
(It is quite an old drive that I suspect I formatted for Mac myself originally, from its default Windows format)
I have just found a Windows PC and am able to read the drive and am taking files off it, right now, but is there any way to change the formatting of the drive back to Mac, without deleting the whole drive and having to start again? (It took about 8 hours to do first time around!)
MacBook Pro 15", macOS 10.14