Hi all, I was running out of space for photos on my MBA, so following suggestions on MacRumors, I bought a Nifty MiniDrive SD adaptor and a SanDisk 200GB MicroSD: https://www.amazon.co.uk/gp/product/B017HOBQ9U/ https://www.amazon.co.uk/gp/product/B00V62XBQQ/ It cost around £100 for the two items. Reformatted the SD to OSX Extended (Journaled), and transferred my 65GB Photos Library to it. Opened Photos, all worked well. Lovely. Closed and opened it a few time, rebooted, all working lovely. A few days later, opened Photos again. Corrupted. Rebuild the library. Photos working again now. A few days later, the Photos library is corrupted again. Rebuilt the library. Working now. But i suspect it will corrupt again in a few days. I don't know what to do here. I tried Disk Utility First Aid, and it says: "First Aid Process has failed. If possible, back up the data on this volume." Under 'More Details' it says "Updating boot support partitions for the volume as required. Unable to unmount boot volume for repair. Operation failed ..." I tested Disk Utility First Aid with another SD card, 128GB, and it ran perfectly fine and gave much the same feedback as running First Aid on a healthy SSD or HDD. Any ideas how to stop the repeat corruption? Computer is a 2013 MBA with 128GB SSD on OSX 10.11.6 El Capitan.