I cannot use cursor arrows to manage screen size. Neither do most of the "window" sizing work.

Hi ​@courageous_ease15B9, I'm just checking in to see if the suggestions helped or if you are still running into this issue? If so, have you had a chance to try these basic troubleshooting steps in this article: https://adobe.ly/48dzRau? Let us know how things are going. Happy to keep troubleshooting with you if needed. Thanks! ^CH

Hey, @courageous_ease15B9. Welcome to the Lightroom Community. I'll need more info to help you figure this out.

Please share the system info from Lightroom Help > System info > Copy and paste into a text document > Upload and attach here.

Please try this step on the external drive:

• Search for Disk Utility from Finder's spotlight search or magnifying glass.

• Run the 'First Aid' diagnostic on the external drive. Check this to learn more: https://adobe.ly/4jbQS7x

• Restart the computer

2 - Ensure Lightroom Classic has the required permissions on the macOS: https://adobe.ly/4gp66Y2

3 - Hold down the Alt (Option) key while launching Lightroom Classic to reset preferences. Confirm the reset when prompted.

Let me know how it goes after following these steps.
Thanks!
Sameer K
(Type '@' and type my name to mention me when you reply)