firefox.exe -P

Hmm, speedup. Do you mean the Refresh feature? Sometimes Firefox may show a bar saying you can speed up Firefox by restoring some default settings. If you click that button, your settings folder is moved to the desktop inside an Old Firefox Data folder, and a new settings folder is created with part of your data. Can you find an Old Firefox Data folder? If so, check inside to see if the semi-randomly-named settings (profile) folder there has freshly updated files. If so... There's no one-click way to "roll back" the refresh, but here is a procedure to revert to your pre-Refresh data. It takes 5 minutes, but that may be faster than recovering individual files and loading those into your new profile. ''Check inside the "Old Firefox Data" folder that Refresh adds to your desktop for a folder with a semi-randomized name. If there's only one, that probably has your old settings and add-ons. If there's more than one, you'll want to work with the one that was updated most recently.'' Once you have identified the profile folder you want to restore, here is my suggested "old profile resurrection procedure": '''Overview''' These are the steps described in more detail below: # Create a new Firefox profile # Remove everything from that new profile folder # Copy in everything from the old profile folder '''Create a new Firefox profile (Windows)''' Exit Firefox completely, and then start up in the Profile Manager by pasting the following into the Start menu search box, or the Start > Run dialog, and pressing Enter: firefox.exe -P ''Note: Any time you want to switch profiles, exit Firefox and return to this dialog.'' Click the Create Profile button, assign a name like OldSettings, and skip the option to change the folder location. Then select that new profile in the dialog and start Firefox. '''Open the New Profile folder in Windows Explorer''' Firefox in the new profile should look like a factory fresh installation. Open the Troubleshooting Information page using either: * "3-bar" menu button > "?" button > Troubleshooting Information * Help menu > Troubleshooting Information * type or paste about:support in the address bar and press Enter In the first table, click the "Show Folder" button. Firefox will launch your brand new profile folder in Windows Explorer. Leaving that folder open, switch back to Firefox, and Exit using either: * "3-bar" menu button > "power" button * (menu bar) File > Exit When Firefox closes, the profile folder should be front and center, or you can activate it using the Task bar. '''Copy Old Data in Place of New''' In that new profile folder you just popped open -- NOT the one on your desktop -- select all the contents (you can use Ctrl+a) and delete (you can press the Delete key on the keyboard). Leaving that window open, open or switch over to your Old Firefox Data folder. Drill down into your old profile folder. At this level you should see a folder named bookmarkbackups among other things. Select everything (Ctrl+a) and Copy (either right-click > Copy or Ctrl+c). Switch to the empty new profile folder in other window and Paste (either right-click > Paste or Ctrl+v). This may take a minute since some of the files are large. '''Start Firefox''' Firefox should start up in that "new" profile with the resurrected old profile data. Success?