Apple has said that some Mac users may not be able to use a scanner and scan copies due to a bug within the macOS. As per a support document by Apple, the company notes that users might see a prompt reading, “you do not have permission to open the application," due to the error. The message will further ask users to contact the computer or network administrator for assistance, indicating the Mac failed to open a connection to the scanner (-21345). Apple says it is working on a permanent fix with a future update. Meanwhile, the Apple support document gives temporary measures as well.
Step 1: Quit any apps that are open.
Step 2: From the menu bar in the Finder, choose Go > Go to Folder.
Step 3: Type /Library/Image Capture/Devices, then press Return.
Step 4: In the window that opens, double-click the app named in the error message. It’s the name of your scanner driver. Nothing should happen when you open it.
Step 5: Close the window and open the app you were using to scan. A new scan should proceed normally. If you later choose to scan from a different app and get the same error, repeat these steps.
Affected users have shared complaints about this issue across the Apple Support Communities, Reddit, HP Support Community, and elsewhere. A user with Apple MacBook Pro 13 wrote on Apple’s discussion forum, “Since the recent update to Big Sur, my Canon Pixma Scanner will not work (non permission error message). Have been in touch with Canon who are aware of the issue but state I must contact Apple. Anyone have an easy fix for me please?" Another user faced a similar problem with an HP scanner. The error message appears to be affecting users on multiple versions of macOS Big Sur.