cannot copy anything on external hard drives. same drives were working very well till today.
I bought my imac 5 months ago. Been using several external hard drives to save my data. used it 3 days ago too. Now today suddenly all external hard drives dont let me copy anything on them. security shows read only. no idea how this happened. tried all tricks. nothing works (
iMac (27-inch Mid 2011), iOS 8.4
