On my MacBook Air, I upgraded to Catalina. The upgrade has rendered my external SSD drive read-only. I also get a warning message that I should back up the drive so it can be formatted. Why is this new Mac OS trying to format my external drive?
MacBook Air
Some of the external disks on the market come formatted in NTFS with a utility to allow macOS to write on them. (Natively, macOS can read NTFS volumes but not write on them.) The reason I inquired about the formatting of yours was to see if you had lost that NTFS-writing program when you upgraded to Catalina, which seemed like the most likely explanation, as Bob suggested.
If you have since verified with Disk Utility that your volume is truly FAT or EXFAT, the above would not apply. (If not, please do so.)
I have not yet tried using a FAT or EXFAT volume with Catalina, so I cannot report any personal experience. Apple's online documentation states that both FAT and EXFAT volumes are supported in Disk Utility.
There were reports in this forum of EXFAT volumes suddenly going read-only in previous versions of macOS. At least one was corrected by resetting NVRAM. (See Reset NVRAM or PRAM on your Mac - Apple Support.) I regret that I have no assurance this will help in your situation.
Some of the external disks on the market come formatted in NTFS with a utility to allow macOS to write on them. (Natively, macOS can read NTFS volumes but not write on them.) The reason I inquired about the formatting of yours was to see if you had lost that NTFS-writing program when you upgraded to Catalina, which seemed like the most likely explanation, as Bob suggested.
If you have since verified with Disk Utility that your volume is truly FAT or EXFAT, the above would not apply. (If not, please do so.)
I have not yet tried using a FAT or EXFAT volume with Catalina, so I cannot report any personal experience. Apple's online documentation states that both FAT and EXFAT volumes are supported in Disk Utility.
There were reports in this forum of EXFAT volumes suddenly going read-only in previous versions of macOS. At least one was corrected by resetting NVRAM. (See Reset NVRAM or PRAM on your Mac - Apple Support.) I regret that I have no assurance this will help in your situation.
To whom should I send the bill for $91.99, which is what it cost me to purchase another 2 TB external drive because the upgrade to Catalina rendered my expensive 2 TB SSD read-only. I spent hours moving all my files from the read-only device to the newly purchased HD. So here's the deal Apple: I will only bill you for the new HD. I won't bill you for my time. I would expect something like this to happen during a Windows update, but a MacOS? Free OS update indeed...harrumph!
What a joke. It was read only because you likely had it formatted NTFS for Windows and you were running a third party app that allowed you to write to it. When you upgraded your forgot to also upgrade the third party app. I'm only speculating because you never answered markwmsn's question. Catalins did not break your drive.
Where shall we send the bill for answering your support question here?
Thanks markwmsn. I appreciate you trying to assist.
I always keep my OS up-to-date. So the last version of MacOS was what was loaded on my 2015 MacBook Air. The SSD was formatted with the basic open formatting (FAT) that allowed both Macs and Windows machines to access it.
Well, if it is an issue with NTFS, it goes to show that Apple really should have enabled write support for that filesystem ages ago already. Why they have left it read-only I will never understand. Every other OS can write to NTFS fresh out of the box.
NTFS is a proprietary Microsoft filesystem. MacOS can not write to it. This is not the fault of Apple. Windows computers can not write to Mac filesystems for the same reason. Please let us knoiw what none Microsoft OS can write to NTFS formatted drives out of the box.
Maybe some additional information would help somebody here help you.
How is your external SSD formatted currently?
What version of macOS was your MBA running before the Catalina upgrade?
Wow. You’re nice.
I had the same issue, I have Seagate External Drive so I downloaded the "Paragon Drive" from Seagate's website and now is back to normal. https://www.seagate.com/support/downloads/
Catalina has made external drive read only
