If you are reading this page, you have probably encountered a problem with Tab Mix Plus. While it can be some unknown bug, most issues reported in the forum usually end up being extensions or theme conflicts.

In order to identify and solve the problem there are several things you can do.

Install latest development version

First, install the latest development version to see if the problem might have been fixed (there's always a development build sticky thread in the Builds forum). You can reinstall the latest official version in place of the development version later if you wish.

If the latest development version still has the problem then the place to post about it is the development build sticky thread in the Builds forum, but before you post there are a few more things to try.

Create new testing profile

Create a new profile (Creating new profile is safe and doesn't have any effect on your current profile, which you can return to using once you complete testing the new profile), install Tab Mix Plus and import your preferences from the problematic profile. If you don't see the problem, it's most likely a conflict with another extension. Install your extensions one by one restarting in between until the issue reappears (once you isolate the conflicting extension(s), you don't have to use the new profile unless you want to).

Disable other extensions

If you prefer not to create a new profile for testing, you can try disabling your other extensions in the current profile instead. Then enable each extension one by one and test for the problem.

Note: This is not as good as creating a clean profile because the conflict may be an option choice or another customization made in the browser and not another extension.

If you have a high number of extensions, a way to expedite this troubleshooting is to disable half of the installed extensions at a time. If the problem disappears, then you know that the conflicting extension is one of those you just disabled.

If this is still a high number of extensions, you can enable half of those extensions and check for the problem. If and when you get to a more manageable number of extensions, you can then enable/disable extensions one at a time until you isolate the one conflicting with Tab Mix Plus.

Reset your profile

Finally, if nothing else works you can reset your profile, read the article Reset Firefox - easily fix most problems from Mozilla support.

Report your finding

When you finish your testing, we encourage you to report about your findings, whether you find the culprit or not, to our forum, so other users can benefit from your findings and to help Tab Mix Plus developers to solve the issue you have. (Read How to post about a problem). In the case the conflict is another extension or theme, please report about it to the developer of the conflicting extension or theme also so that they can work it out as well.

Most issues reported in Tab Mix Plus forum usually end up to be extensions or theme conflicts.

When posting, please, always include your OS (Operating System), Firefox and Tab Mix Plus versions. A list of your extensions could also be useful as somebody might spot a troublesome extension which can lead to a faster resolution.
You can set your OS, Firefox and Tab Mix Plus information in the signature field in your profile (link to the User Control Panel is at the top of every page of the Forum). This way, you won't have to type it every time. Just remember to update it with Firefox and/or Tab Mix Plus update!
It is very helpful if you can post the steps to reproduce your problem and if you experience an issue with a specific page, include a link(-s).

Add attachment to your post
Follow these steps to attach a file or a screenshot to your post to the Forum:

1. In your thread, click Full Editor button under the quick reply box.
2. Locate Filename and Browse buttons, click and navigate to the file you just saved.
3. Click Add File and Submit. Your file will be attached to your post.

Save Troubleshooting Information from Firefox

Use Firefox Troubleshooting Information page to help us fix issues with Tab Mix Plus. Use Copy text to clipboard button on the Troubleshooting page and save the data to a text file. There are also a few extensions to help you with posting such info in forums, like Infolister and Extensions List Dumper.

Save Tab Mix Plus Preferences
You may be asked to post your Tab Mix Plus preferences. To do that, follow these steps:

1. Open Tab Mix Plus Options and click the 'Preferences' button at the bottom left corner.
2. Choose 'Export Preferences' and save the file to a location on your hard drive.

Save Browser Console log

The Browser Console is a tool provided by Firefox to log errors, warnings and messages for all content tabs, for add-ons, and for the browser's own code.

The content of the Browser Console can provide important information about your problem. To get this information, open the Browser Console (Tools > Web Developer > Browser console) when you encounter the problem you want to report about, right click anywhere in the console and click select all. Copy everything and paste it to a text file.

If your problem happens when Firefox starts, open the Browser Console immediately after Firefox starts and copy/paste its content to a text file, then clear the content and open new window and copy/paste the Browser Console content to another file.

Where to post
To help the developers and users to track issues and get better search results, please remember to post all your issues to our Github repository.

Thank you for your cooperation and Good Luck! 

If the Error button in the Tab Mix Plus Options is visible, some of your extensions are incompatible with Tab Mix Plus. It is recommended you disable or uninstall the extensions in the list. Click the "Show List…" button to do that.

Conflicts have been reported with Ubuntu Firefox Modifications extension, so if you use Ubuntu, disable that one (you can read more here).

Conflicts with BarTab, Colorful Tabs and Tree Style Tab have been reported. Since all these extensions manipulate tabs, shouldn't be surprising. Don't panic, these conflicts are usually solved rather quickly, especially if good information is given (like errors in console, screenshots, steps to recreate, etc.). Feel free to post and provide as much info as possible.

Issues with MR Tech Toolkit have been reported with Firefox 22 and up. Those are not Tab Mix Plus problems but rather MR Tech Toolkit. There's really no reason any longer to have MRTT installed - it hasn't been updated for years. Some of its functions are now Firefox default, others can be replaced with other extensions. (More reading about this issues)