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I cannot print, get error 'An unknown error occurred while printing."

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New Contributor

I cannot print, get error 'An unknown error occurred while printing."

I can see that hundreds of other people also have this problem and I can't understand why Mozilla don't fix it.

When I go to print an email or a receipt, whether by printer or by PDF, I *sometimes* get the error, 'An unknown error occurred while printing.'

It is very frustrating as the problem is intermittent. Sometimes it works, sometimes it doesn't... even with the same page being printed. Incidentally, that page can be printed in both Chrome and Internet Explorer without a problem.

I have tried other "solutions" in similar, now closed, threads. However, 'reset' is not working for me. Closing Firefox and reopening doesn't work either. I have the latest version of Firefox: 14.0.1 and have Windows x64. There is enough available space in the cache...

I'm just at my wits end with this.

8 REPLIES
All Star Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

New Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

This was the first help page I went to when I was trying to resolve my problem, hence the reason I mentioned that the 'reset' solution didn't work for me.

There is nothing else on that help page of use. Sorry!

All Star Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

Apparently there is a printer troubleshooter in Windows. Maybe try that to make sure that you are using the correct printer drivers? If that gives you no clues, backup your profile and create a new one and see if that helps.

Support Forum Moderator

Re: I cannot print, get error 'An unknown error occurred while printing."

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

  1. Go to Firefox > Help > Troubleshooting Information.
  2. Click the "Reset Firefox" button.
  3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
  4. Firefox will open with all factory defaults applied.


Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

New Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

In my case I had to do the following:

- Set default printer to an online printer (like PDF Creator). Default was set to an offline printer before. This setting is changed in control panel not in Firefox.

- PDF File name should not be copied from rich text (as it appears to have some problems and sometimes special characters). File name must be plain text.

New Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

same problem: print test page works, but no way to print from any other application

Support Forum Moderator

Re: I cannot print, get error 'An unknown error occurred while printing."

If you can't print from any application, your problem is beyond a Firefox support issue. I suggest a support forum for your brand printer, or a support forum for your operating system (i.e., Windows, Mac oSX, or Linux).

New Contributor

Re: I cannot print, get error 'An unknown error occurred while printing."

With the latest updates FF 19 BETA and Acrobat X. The new one with the black PDF screen), I'm having difficulty too printing to Adobe PDF. System Win 7 x 64.

Printing to physical printers not an issue.

No errors, but (Not Responding either in FF or Acrobat.) Printing to the PDF printer directly sometimes works. Using the work-around fast enough, it seems to always work.

I found a work-around:

Goto Print Preview Select Print Type in your file name IMMEDIATELY press OK and Minimize Firefox.

All of the progress boxes/windows are getting confused otherwise. With FF opened as a normal page, there are too many different progress boxes. Acrobat has one, the windows print driver has one, FF seems to have one and they all can't be on top.

They will if FF is minimized.

Incidentally if FF is killed, the "Creating Adobe PDF" shows its face from being hidden.

I did reset Firefox.

This is seriously messed up now. It used to work fine until the last round of updates from M$, Adobe and FF.