The operation can’t be completed because you don’t have permission to access some of the items.

Hi filers,

Thank you for using the Apple Support Communities! It appears you are receiving an error about permissions when you are attempting to perform an action on your Mac. I'd like to see how I can help.

Without having more details about when you are receiving this alert, I would like to share a few articles with you that do relate to fixing permission issues on Mac. Take a look at them below, and see if they help:

-If you don’t have permission to open a file or folder on Mac - Apple Support.

-Change permissions for files, folders, or disks on Mac - Apple Support.

If this does not help solve the issue you are experiencing, I would like to hear back from you. Please share more details as to what action are you attempting to perform on your Mac, and any other helpful details you'd like to share.

Best regards.