Hi Ashutosh Soni, sorry to hear about this problem. Does this affect all pages -- no pages can be bookmarked -- or is there a pattern to which pages cannot be bookmarked? '''Could you test in Firefox's Safe Mode?''' In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem. ''If Firefox is not running:'' Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) ''If Firefox is running:'' You can restart Firefox in Safe Mode using either: * "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled * (menu bar) Help menu > Restart with Add-ons Disabled and OK the restart. ''Both scenarios:'' A small dialog should appear. Click "Start in Safe Mode" (''not'' Refresh). Any improvement? '''Could you check the bookmark-history database?''' The Troubleshooting Information page has a "Verify Integrity button to do a little light maintenance on the Places database (where bookmarks and history are stored). You can open that using either * "3-bar" menu button > "?" Help > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste about:support in the address bar and press Enter Then scroll way down or use Find to search for ''Integrity'' in the Places Database section. At first, nothing will seem to happen, but then several seconds after clicking the button Firefox should report some diagnostic results below it. Any improvement? If not, you could copy/paste those results.