This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Get download error popup message with with a long string of characters every time firefox is opened. It can be closed, FF downloads work OK.

  • 9 replies
  • 1 has this problem
  • 12 views
  • Last reply by FredMcD

more options

Every time Firefox 40.0.3 is opened a separate popup message message window entitled "Download Error" with the text: Firefox could not download the search plugin from: data:text/html;base64, Following the base64, there is a long string of characters e.g. PFNlYXJjaFBsdWdpbiB4bWxucz0iaHR0cDovL etc. etc. etc. the string goes on with over 3,600 characters.

The window can be closed and Firefox works OK, the search is fine with Google, DuckDuckGo, and Ixquick. I don't want to install a new search engine. There are no viruses I can find. Windows is up to date. This just started. I tried to attached a jpg screen shot, but it is taking too long.

A screen shot is attached with the string.

Every time Firefox 40.0.3 is opened a separate popup message message window entitled "Download Error" with the text: Firefox could not download the search plugin from: data:text/html;base64, Following the base64, there is a long string of characters e.g. PFNlYXJjaFBsdWdpbiB4bWxucz0iaHR0cDovL etc. etc. etc. the string goes on with over 3,600 characters. The window can be closed and Firefox works OK, the search is fine with Google, DuckDuckGo, and Ixquick. I don't want to install a new search engine. There are no viruses I can find. Windows is up to date. This just started. I tried to attached a jpg screen shot, but it is taking too long. A screen shot is attached with the string.

All Replies (9)

more options

I made a smaller jpg and sent a screen shot.

more options

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

  • Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
  • Do NOT click the Reset button on the Safe Mode start window
more options

I tried that before I posted the question. The popup comes on as soon as Firefox starts , it shows up first = before completely Firefox opens. There is no change in safe mode with the default theme.

Thank you.

more options

Please install and use

Places Maintenance {web link} Allows to run Maintenance tasks on the database that drives Places, the bookmarks and history module behind Firefox.

more options

Open the Download Manager <Control> J and see if it is listed here.

more options

Ran the Places Maintenance - no change, I have the same behavior as I stated earlier Safe Mode or not, the error message displays instantly when I click on Firefox. It is the same string of characters.

The Download Manager does not show any downloads.

more options

This looks like a search plugin in base64 format. Do you have a searchplugins folder in the profile folder that contains files?

Try to delete the search.json file and possible search-metadata.json and search.sqlite files in the Firefox profile folder to reset the search engines to the default.

You can use this button to go to the current Firefox profile folder:

Firefox will rebuild the search.json file from the default built-in search engines that come with Firefox and the searchplugins folder in the Firefox profile folder.

more options

Sorry, I have out of town for a while.

The searchplugins folder containers one file; “ixquick-https.xml”.

I deleted: searchplugins folder search.json file search-metadata.json file search-metadata.json.tmp file

There is no search.sqlite file

There is signons.sqlite file; I deleted that too.

No change. The same error opens immediately.

SOOOO. I set up a new profile and the error is gone. Yes, I had to rebuild my add-ons etc. but the error is gone, it is embedded somewhere in the old profile. I’ll go through deleting and replacing folders and files in old troublesome profile until I find the error.

Thank you for your interest.

Modified by Joe-

more options

That was very good work. Well Done. Please flag your last post as Solved Problem so others will know.