Computer failed to open Envy Photo 7800 scanner -21345

[Namvet1969]

Computer doesn't connect to scanner, which previously no problem

[Max3Aj]

@Namvet1969, Welcome to the HP Support Community – it’s great to have you here!

I appreciate you taking the time to share your question. I'm more than happy to assist with this and provide a solution that works for you.

The scanner error -21345 on your HP ENVY Photo 7855 running macOS 15.0 Sequoia typically indicates a communication or hardware issue. Since it was working previously, this may be due to macOS updates, driver conflicts, or scanner calibration problems.

Please follow these steps to resolve the issue:

Reset the Printer

This clears temporary faults:

• Turn off the printer.
• Unplug the power cord from both the printer and wall outlet.
• Wait 60 seconds.
• Plug it back directly into a wall outlet (avoid surge protectors).
• Power it on and try scanning again.

Check Scanner Bar Functionality

• Open the scanner lid.
• Press the Copy button.
• Watch if the scanner light moves across the glass.
  • If it doesn’t light up or move, it may be a hardware fault. 

Reinstall the Printer on macOS

• Go to System Settings > Printers & Scanners.
• Remove the HP ENVY Photo 7855.
• Download and install the latest HP Smart app from 123.hp.com.
• Use the app to re-add and configure your printer.

Use HP Smart’s Diagnose & Fix Tool

• Open HP Smart.
• Click the printer dropdown (top menu bar on Mac).
• Select Diagnose & Fix.
• Follow the on-screen instructions to auto-detect and resolve issues.

Update Printer Firmware

• Open HP Smart > Printer Settings > Advanced Settings.
• Check for firmware updates and install if available.

Restore Network Settings (if using Wi-Fi)

• On the printer touchscreen:
  • Go to Setup > Network Settings > Restore Network Settings.
• Reconnect to Wi-Fi and re-add the printer via HP Smart.

Scanner Failure error on HP printers (Windows, macOS) | HP® Support
HP printers - Scanner not found or connected (Windows, macOS) | HP® Support
 

I hope your issue is now resolved. If not, feel free to reply and we’ll continue helping until everything’s sorted!

If the post helped, please click “Accepted Solution” to help other users easily find it. And if you’d like to say thanks, just tap the “Yes” button!

Cheers,

Max3Aj

HP Support

[Namvet1969]

Thanks for your help, but the problem still persists. I followed all of your steps! When I loaded HP Smart it asked to do a test scan and it worked but when I access the scanner through Printers and Scanner in System Settings it doesn't connect. I can print but only not scan. Thanks again, I guess I'll keep trying

[Garp_senchau]

Hi @Namvet1969 ,

Thank you for your response

My colleague @Max3Aj is currently out, but don't worry – I’ll be taking over and making sure we get this sorted for you.

scan directly from macOS (through the Printers & Scanners section). Since printing works but scanning doesn’t, it could be a conflict between macOS and the system settings for scanning.

Here are a few additional steps specific to macOS that might help resolve the scanning issue:

Check the Scan Settings in Preview & Image Capture

Preview App: Open Preview and select File > Import from Scanner.

If the scanner works here, it might just be a problem with the system settings for scanning.

Image Capture App: Go to Applications > Image Capture. This app often allows scanning functionality to work better with macOS than the default Printers & Scanners.

If the scanner appears in Image Capture, select it, and try scanning from there.

If these apps work but Printers & Scanners doesn’t, it suggests macOS might be having trouble with the scan setup.

Check for Scanner-Related Drivers and Updates

Even if you’ve updated using the HP Smart app, macOS can have specific drivers for scanner functionality.

Go to System Settings > Printers & Scanners.

Select your printer, then click Options & Supplies > Driver. Ensure the correct driver is selected for scanning.

You can also check HP Software for any additional scanner drivers or settings by visiting the HP Support page.

Check macOS Permissions and Privacy Settings

Go to System Settings > Security & Privacy > Privacy.

Under Files and Folders, ensure HP Smart and Preview have the appropriate access permissions to scan documents.

Try Scanning Using a USB Connection

If you're using Wi-Fi, try connecting your HP ENVY Photo 7855 directly to your Mac using a USB cable. This can help determine if the issue is network-related.

Reinstall the printer via System Settings and test scanning again after connecting via USB.

I hope this helps.

Please feel free to reply here if you have any questions or if you need further clarification on any of the steps. 

Take care and have a good day. 

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Regards,