In case it is relevant: I am using the following Extensions:

Always Right Duplicate Tabs Closer Ghostery Image Reader(OCR) Saka Key Toggle Font TouchpadSwipe

[v57+] Places Maintenance is built into Firefox.

Type about:support<enter> in the address bar.

You will find Places Database near the bottom. Press the Verify Integrity button.

When done, copy and post the results here.

Are you using Sync to sync the bookmarks ?

FredMcD said

[v57+] Places Maintenance is built into Firefox. Type about:support<enter> in the address bar. You will find Places Database near the bottom. Press the Verify Integrity button. When done, copy and post the results here.

Hello, thank you for the reply

I did the Verification and Here is the result:

> Task: checkIntegrity + The places.sqlite database is sane + The favicons.sqlite database is sane > Task: invalidateCaches + The caches have been invalidated > Task: checkCoherence + The database is coherent > Task: expire + Database cleaned up > Task: originFrecencyStats + Recalculated origin frecency stats > Task: vacuum + Initial database size is 20480KiB + The database has been vacuumed + Final database size is 5120KiB > Task: stats + Places.sqlite size is 5120KiB

Looks fine?

cor-el said

Are you using Sync to sync the bookmarks ?

I am using built-in Sync to sync - Bookmarks - History - Open tabs - Login and Passwords - Preferences but not any other Extensions

Thank you

Let me put the updates here:

- [20200301_Sun_065503]

 Some Additional info: seems I can Modify existing folders/entry, but cannot create new folders/entry in "Library"
 still can add entry from main UI though

- [20200301_Sun_065712]

 Also, I can add folder in 
 "Edit This Bookmark"
 ⇒Folder
 ⇒Choose Folder
 ⇒New Folder

well then I dont know how to delete it...Orz

- [20200301_Sun_065948]

 I tried editing in Bookmarks⇒Show All Bookmarks
 or access the Library by ｢chrome://browser/content/places/places.xhtml｣, which I usually do to view Library in Main UI

- [20200301_Sun_070129]

 I assume the problem lies with the Library in the new version, based on the following facts

- it happens on 2 company computers(Windows 10 Pro, and Enterprise), which does not sync with each other(Security Policy) - it happens on my Laptop in home (Windows 10 Pro), and my Macbook in home(Mojave), which Sync through this account

 ★Thus I believe it not the profile/data problem?

I wonder where I should report this? Thank you

Using Sync to sync bookmarks to a mobile device has been reported quite a few times causing issues with organizing bookmarks.

Does it work better if you temporarily disable Sync ?

If you use Sync then best is to disconnect Sync temporarily during troubleshooting.

If "Verify Integrity" cannot repair places.sqlite, rename/remove all places.sqlite and favicons.sqlite files in the Firefox profile folder. Firefox will rebuild places.sqlite and restore the bookmarks from a recent JSON backup in the bookmarkbackups folder.

• keep a backup copy of places.sqlite in case a new places.sqlite database has to be created

See also:

• https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file
• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

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.

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/Profiles

@cor-el

Thank you for your solution protocol, I will try it later

Meanwhile for those who have similar problems, I seem to be able to delete Folders on iOS

Although Seperater still remain a problem as they are not shown on iOS

Thank you folks a lot.

From staunch Firefox User