Set up Read/Write Permissions in iMove

And things are working again after following earlier suggestion of Settings -> Privacy & Security -> Media & Apple Music -> enable iMovie

Not the seamless upgrade experience that I have become used to with Apple...

I don't know if this will work, but try this: Control-click on the library's icon and choose Get Info from the pop up menu. In the Get Info box that appears, at the bottom of the box will be a permissions section. Confirm that you have read and write permissions. If you change permissions, be careful that you don't give yourself "read only" permissions or you won't we able to write to the library.

-- Rich

Try going to SETTINGS-PRIVACY AND SECURITY-MEDIA AND APPLE MUSIC. Does iMovie have access?

Big Ron22 wrote: I get this this message Permission error opening Ron's Library ...

That is not normal.

Is your iMovie Library in your user account Movies folder (the default location)? (that is, Users > youruseraccount > Movies)

Did you copy or move your iMovie Library from its original location to a different folder, drive or Mac? If so, the permissions for that folder or drive may be interfering with your ability to open the Library with iMovie.

Are you using a different Mac or user account from the one in which you created the iMovie Library in the first place?

Not normal, but not unique. I am an occasional iMovie user. I last used it the beginning of September, while running Tahoe. All was well.

Today, I see same behaviour. The only changes of significance between iMovie working and iMovie barfing are:

1. upgrade to Golden Gate the day it came out
2. upgrade to 27.0.1 the day it came out
3. upgrade iMovie to 10.4.5 on Oct 1

Today was the first time running iMovie after these changes. Here's what happened:

1. launch iMovie
2. it asks to select library, showing existing library
3. select
4. fails with "Permission error opening iMovie Library 1"
5. Click OK and iMovie quits
6. Run again, but select New... instead of picking existing library
7. use suggested folder (iMovie Library 2) in suggest location (Movies folder)
8. iMovie runs
9. quit and run again
10. it now asks me to pick from two existing libraries
11. pick the new library that was just created
12. fails with "Permission error opening iMovie Library 2"

I am hopeful that someone from Apple can offer explanation and solution, saving me the hassle of making AppleCare support call...