How to Fix “Failed to Open a Connection to the Device (-21345)” Scanner Error on macOS Sequoia

After upgrading to macOS Sequoia v15, many users have discovered that their scanners have stopped working, even though they were functioning perfectly before. When trying to scan a document, a common error message appears:

“Failed to open a connection to the device (-21345)”

This issue has been widely reported on forums and across various Apple support threads. Both Brother and Epson scanner users seem to be affected, especially when using printers connected wirelessly.

What Caused the Error?

The issue appears to be related to new privacy and network permissions introduced in macOS Sequoia. The system may be preventing scanner applications from communicating with devices on the local network unless access is manually granted.

Even if your printer/scanner is already connected and visible, the scan function may fail unless network access is properly configured.

Devices Reported to Be Affected

Brother MFC-J985DW (wireless)
Epson Artisan 810
Likely other AirPrint-compatible or Wi-Fi-connected multifunction printers

How to Fix -“Failed to Open a Connection to the Device (-21345)”

Fix 1: Enable Access in Privacy Settings

This is the most widely reported fix:

Open System Settings.
Go to Privacy & Security.
Select Local Network.
Enable access for your printer or scanner if listed.

If your scanner or printer app appears in this list but isn’t enabled, the system may be silently blocking the connection.

Fix 2: Run the Scanner Driver Manually

If your device isn’t listed under Local Network:

Close all open apps.
In the menu bar, go to Finder > Go > Go to Folder…
Enter the following path:
/Library/Image Capture/Devices
Locate the app listed in the error message.
Double-click it. (Nothing visible will happen — that’s normal.)
Try scanning again.

This simple step has worked for several users and appears to “wake up” the scanner process.

Additional Steps That Helped

Reboot both the Mac and the printer.
Unplug and replug the printer after a few minutes.
Try a USB connection if wireless continues to fail.
Ensure the latest drivers are installed from the manufacturer’s website.

Still No Access in Local Network Pane?

Some users found that their scanner or printer app does not appear at all in the Local Network section, and no option to add it exists. This may be a bug in macOS Sequoia 15.3.1, especially on newer M4-based iMacs. In this case, the “Go to Folder” method listed above is the most effective known workaround.

Conclusion

The “Failed to open a connection to the device (-21345)” error on macOS Sequoia appears to be related to privacy restrictions or app permissions, especially for devices using wireless connections. The issue can usually be resolved by adjusting Local Network access settings or by manually initializing the driver.

Until a full patch is released by Apple or printer vendors, these workarounds can help restore scanner functionality on both Intel and Apple Silicon Macs.