iMovie update causes hang

For some reason iMovie 10.3 has demonstrated some odd issues. First thing is to make sure that you have enough free space to download the app.

If sufficient space, and if Ian's good suggestion to try Deleting Preferences doesn't solve it, try these other diagnostic procedures:

Safe Mode

Try booting up in Safe Mode (see Finder menu for instructions) and, after everything loads, immediately shut down and reboot in normal mode. Then see if iMovie works properly.

Opening iMovie in a new user account

Create a new user account from System Preferences/Users and Groups and try to open and use iMovie in the new account.

You can use the Guest account on your Mac for this purpose.

Opening iMovie in a new library

Try opening iMovie in a new library.  To do that, open iMovie while holding down

the Option key and then selecting to create a new library in the box that

appears.

Resetting the System Management Controller

Try resetting the System Management Controller (but no longer available for the new M1 computers):

https://support.apple.com/en-us/HT201295

Resetting the NVRAM or PRAM

Try resetting the NVRAM or PRAM:

https://support.apple.com/en-us/HT204063

Contact Apple Support

If none of the above resolve your issue, contact Apple Support.  The techs there have the capability of remotely accessing your computer that we cannot do here.  To contact apple support click on the Get Support item in the upper right hand corner of this forum’s screen.  Navigate to a place where you can enter your phone number.

-- Rich

I would not upgrade to Monterey at this time. There have been some performance issues with iMovie running on Monterey, that have not yet been worked out. So I would wait awhile.

Here's a link that explains how to boot in Safe Mode.

https://support.apple.com/en-us/HT201262#issue

Regarding starting in a new library, in the box that appears when you open iMovie while holding down the Option key, actually select to create a brand new blank library. We want

Finally, to rule out a conflict in your user account, try opening iMovie in your Mac's guest account. Alternatively, you can create a new user account by going to System Preferences/Users and Groups.

In the event that you try all of the suggestions in this thread, and still have no success, then try calling Apple Support. The techs there have the capability of remotely accessing your computer that we cannot do here.  To contact apple support click on the Get Support item in the upper right hand corner of this forum’s screen.  Navigate to a place where you can enter your

phone number.

-- Rich

It is quite easy to install a second OS on a Mac to test whether it is OK and how apps behave.

Using Disk Utility you create a new partition on your hard drive and install the new OS on that.

You can then boot into either the old or the new operating systems to test apps etc. on either partition.

If you decide you don't need the new partition any more you can easily delete it and the Mac is back in its original state.

Try deleting the preferences.

Launch iMovie whilst holding down the Command and Option keys.

In the window that opens click Delete Preferences.