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Why do I have two sets of all Firefox plugins and extensions on my computer?

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I am using a PC with fully updated Windows 7 Home Premium, Service Pack 1, 64 Bit. I use CCleaner to keep it running smoothly. Today, I noticed that I have two copies of every Firefox plugin and extension on my computer, and all were set as 'enabled' on computer start up. Each extension has the 'default copy', and another marked 'default-15...' (I am unable to see any of the file name after the '-15...'). Before these extra files appeared, I had configured and reconfigured, tweaked and re-tweaked, and even uninstalled and re-installed Firefox in an effort to speed up (and sometimes re-start) search capabilities. Was also trying to fix all video formats not playing correctly on multiple websites. Everything was working so slowly since updating to 57, the phrase, Firefox: "Quantum of Slowness" became permanently embedded in my mind. I have FINALLY found the right combination of Options and Tweaks (disabling many items with CCleaner) to make my Firefox blazing fast, and ALL videos everywhere work correctly. I do not want to be required to Refresh Firefox at this point. How do I get rid of these duplicate files? Thank you in advance for any assistance you may be able to provide me.

I am using a PC with fully updated Windows 7 Home Premium, Service Pack 1, 64 Bit. I use CCleaner to keep it running smoothly. Today, I noticed that I have two copies of every Firefox plugin and extension on my computer, and all were set as 'enabled' on computer start up. Each extension has the 'default copy', and another marked 'default-15...' (I am unable to see any of the file name after the '-15...'). Before these extra files appeared, I had configured and reconfigured, tweaked and re-tweaked, and even uninstalled and re-installed Firefox in an effort to speed up (and sometimes re-start) search capabilities. Was also trying to fix all video formats not playing correctly on multiple websites. Everything was working so slowly since updating to 57, the phrase, Firefox: "Quantum of Slowness" became permanently embedded in my mind. I have FINALLY found the right combination of Options and Tweaks (disabling many items with CCleaner) to make my Firefox blazing fast, and ALL videos everywhere work correctly. I do not want to be required to Refresh Firefox at this point. How do I get rid of these duplicate files? Thank you in advance for any assistance you may be able to provide me.

Chosen solution

Hello cor-el, In Windows 7 (64 Bit)" I had already deleted old Firefox folder, but still had doubles of all extension and plugin files on my computer. I had checked about:profiles but only one profile was listed. I decided to completely uninstall Firefox , including APPDATA and Firefox files. In order to save myself a whole lot of headaches, I followed these steps: 1. In 'Windows Features', I clicked 'Internet Explorer' back on and restarted computer to make it easy to find in 'Start Menu'. 2. Using the menu bar, I exported all of my Bookmarks to HTML. 3. I 'Refreshed Firefox' to save all of my 'logins' (logins.json and key3.db). 4. I sent (logins.json and key3.db) to 'downloads', then put them in a zip file, to ensure they would not be lost during uninstall. 5. I deleted the 'Old Firefox Data' file. 6. I uninstalled Firefox. 7. I deleted Firefox folder from '%APPDATA%' and checked to be sure C:\Program Files\Mozilla Firefox and C:\Program Files (x86)\Mozilla Firefox were gone. [I Discovered that you cannot 'copy and paste' old logins.json and key3.db to new profile when you only have one Firefox profile, so I: 8. Deleted key3.db from my new (and only) profile. [logins.json had not yet been created in my new (only) Firefox profile. 9. Opened zip file containing old login info. 10. Drag and Dropped both old files to my profile. At this point, all duplicate files had been removed from my computer, and all of my hundreds of bookmarks, logins, and passwords had been preserved. That is how I 'Resolved this problem'.

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default-15... if that numeric string is like 10 -12 numbers that Profile is a Refreshed Profile, IOW the "default" Profile that was cleaned up. And you would have seen an Old Firefox Data folder on your desktop after the Refresh was performed.

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Hello the-edmeister, Thank you for explaining what the 'default-15...' files are, but I would still like to know how to delete these duplicate files/extensions (and which ones to delete) because I don't want all of these duplicate files on my computer.

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You can remove the "Old Firefox Data" folder on the desktop it you no longer want to use it and recover more personal data.

You can copy files like these with Firefox closed to the current profile folder to recover specific data. Note that you should be cautious with copying SQLite database files if you previously had problems.

  • bookmarks and history: places.sqlite
  • bookmark backups: compressed .jsonlz4 backups in the bookmarkbackups folder
  • cookies.sqlite for the cookies
  • formhistory.sqlite for saved form data
  • logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
  • cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager
  • persdict.dat for words you added to the spelling checker dictionary
  • permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences
  • sessionstore.jsonlz4 for open tabs and pinned tabs

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

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Chosen Solution

Hello cor-el, In Windows 7 (64 Bit)" I had already deleted old Firefox folder, but still had doubles of all extension and plugin files on my computer. I had checked about:profiles but only one profile was listed. I decided to completely uninstall Firefox , including APPDATA and Firefox files. In order to save myself a whole lot of headaches, I followed these steps: 1. In 'Windows Features', I clicked 'Internet Explorer' back on and restarted computer to make it easy to find in 'Start Menu'. 2. Using the menu bar, I exported all of my Bookmarks to HTML. 3. I 'Refreshed Firefox' to save all of my 'logins' (logins.json and key3.db). 4. I sent (logins.json and key3.db) to 'downloads', then put them in a zip file, to ensure they would not be lost during uninstall. 5. I deleted the 'Old Firefox Data' file. 6. I uninstalled Firefox. 7. I deleted Firefox folder from '%APPDATA%' and checked to be sure C:\Program Files\Mozilla Firefox and C:\Program Files (x86)\Mozilla Firefox were gone. [I Discovered that you cannot 'copy and paste' old logins.json and key3.db to new profile when you only have one Firefox profile, so I: 8. Deleted key3.db from my new (and only) profile. [logins.json had not yet been created in my new (only) Firefox profile. 9. Opened zip file containing old login info. 10. Drag and Dropped both old files to my profile. At this point, all duplicate files had been removed from my computer, and all of my hundreds of bookmarks, logins, and passwords had been preserved. That is how I 'Resolved this problem'.