I bought a 4TB external drive last year. I created two partitions: one to hold a Carbon Copy Cloner backup of my iMac and the other to be a generic external drive.
CCC has been working great but I have had the devil’s own time simply copying files to the external partition.
For security reasons that were a holdover from my MacBook days, I have created an Administrator user account and a Mike user account (which I use all the time). The Mike user does not have all the power of the Administrator, by design: if some bad software wants to write to the drive, it will not have the permission to do so. When installing software or making some changes, I have to enter the Administrator credentials to carry out the operation. It can be tedious sometimes, but it does not happen often and I’m used to it.
I think, too, Apple’s recent emphasis on security in its operating system releases have raised some barriers that weren’t there before. I don’t remember, for example, having this much trouble doing simple file management operations on an external drive. Even simply creating a folder or copying a file required me to enter my Administrator credentials for every single operation.
I finally got fed up this morning, Googled around, tried some things, and discovered the fix.
The first thing I did was follow Apple’s instructions for changing permissions in the Home directory and perform the same procedure for the external drive. No joy.
The second thing I did was so incredibly simple I almost wept: from the partition’s Get Info window in the Finder, check the option “Ignore ownership on this volume.” I checked the box and immediately was able to create folders, move and copy files, etc. O frabjous day! Thanks, Larry Jordan!