Hello there,

This is likely to be caused by corrupt places.sqlite database file in Firefox. For further details please see: https://support.mozilla.org/en-US/questions/956552

Hope this helps!

Machine Master said

Hello there, This is likely to be caused by corrupt places.sqlite database file in Firefox. For further details please see: https://support.mozilla.org/en-US/questions/956552 Hope this helps!

I don't think that 3 year old support article about Firefox 19 on a Mac, where the user only had a couple of hundred bookmarks is an appropriate reference.

This user has Firefox 47 on Windows 10 and has 12,000 bookmarks!

edit: spelling correction

DGuerra said

I have around 12000 bookmarks. It has been difficult to trim this down because I can only erase a few at a time. After deleting the entry or entries, the list freezes and to erase more I must close it down and open it again. This happens both with the side bar and the full bookmarks window. I have to close down the window or the bar and open it again.

IMO, the first thing to do is to run Places Maintenance to clean-up the places.sqlite file. https://addons.mozilla.org/en-US/firefox/addon/places-maintenance/\ And keep an eye on the Task Manager - Performance CPU Usage % meter while the "maintenance" process is running; it will take a bit of time to run to conclusion.

Then see if there is a speed improvement when deleting bookmarks. But don't expect it work anywhere near "fast". Deletion or re-arrangement of bookmarks is slow even with 1/4 the number of bookmarks that you have. And with Firefox saving browsing history (seemingly) forever now-a-days, that's a hell of a lot of data for "Maintenance" to deal with.

Best advice I can offer is to delete small amounts of bookmarks at a time and watch the CPU Usage meter and delete the next small batch of bookmarks when the CPU meter drops, indicating that Firefox has 'absorbed' the deletions and is ready to proceed. Push it too fast and data may get lost, or the PC may freeze up.

But I gotta tell you that I have never had more than 3000 bookmarks, and don't run anything close to "state of the art" hardware and never a new operating system. Currently Win7-32 Bit and AMD 3.2 GHz 4-core processor with only 4GB of RAM.