HP Printer Error Code 29 — What It Means & How to Fix It

What Does This Error Mean?

Error 29 means the printer failed to initialize its output bin or finishing device. This is most common on HP printers with an attached stacker, stapler, or mailbox unit. The output accessory is not responding and the printer cannot proceed.

Affected Models

HP LaserJet 8100 Series
HP LaserJet 8150 Series
HP LaserJet 4100 MFP
HP LaserJet 4345 MFP
HP LaserJet 9000 Series

Common Causes

The output accessory (stacker, stapler, or mailbox) is not properly connected to the printer
The cable connecting the output device to the printer is loose or damaged
The output accessory has an internal hardware failure
A paper jam inside the output accessory is preventing it from initializing
The printer firmware does not recognize the connected output accessory model

How to Fix It

Turn off the printer and disconnect the output accessory from the back or side of the printer.

Refer to your printer manual to find the exact connection point for your output accessory model.
Check the output accessory for any jammed paper. Open all its doors and remove any sheets stuck inside.

Even a single sheet of paper caught in the accessory's internal rollers can prevent it from starting up.
Inspect the connection cable between the printer and the accessory. Make sure it is firmly plugged in at both ends.

Try unplugging and firmly re-plugging the cable — a loose connection here is a common cause of error 29.
Turn the printer back on with the output accessory disconnected to see if the printer operates normally on its own.

If the printer works fine without the accessory, the accessory is the source of the problem.
Check HP's support website for firmware updates for both your printer model and the output accessory model.

Firmware mismatches between the printer and its accessories can cause initialization errors like error 29.

When to Call a Professional

If disconnecting and reconnecting the output accessory does not clear error 29, the accessory itself may have failed. Output accessories are expensive to replace new, but refurbished units are often available. A technician can test the accessory separately to confirm if it is the source of the fault.

Frequently Asked Questions

Can I still print without the output accessory?

Yes. If you disconnect the output accessory and the printer initializes normally, you can print to the standard output tray. You will lose the stacking, stapling, or mailbox functionality, but the printer will still work.

What is a stacker or mailbox unit?

These are add-on units that attach to office HP printers. A stacker collects and neatly stacks printed pages. A mailbox sorts pages into separate bins, which is useful in shared office environments where multiple people use the same printer.

Is error 29 covered by HP warranty?

If the printer and output accessory are still under warranty, HP will typically repair or replace the faulty unit. Contact HP support with your product serial number. Out-of-warranty units will require paid repair or replacement.