https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

User saved words don't get saved to the actual dictionary, they are saved to a file named persdict.dat in the Profile folder. (personal dictionary)

FredMcD said

https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

No, I've no such software installed. All other changes, like my browser customizations, or other, get saved.

the-edmeister said

User saved words don't get saved to the actual dictionary, they are saved to a file named persdict.dat in the Profile folder. (personal dictionary)

That is my problem. They don't get saved and every new session, I've to add the same words to dictionary. I'm using one default dictionary only. No customization has been done by me in this regard.

I'm using latest version of FF, i.e. 68.0.2 32bit

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Open the persdict.dat file in a text editor and add something. Does it save properly?

Yes. Even if I add the words to dictionary in safe mode and then reopen in safe mode, it still behaves the same.

Have you tried my other suggestions?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Did you check if Firefox is creating a persdict.dat file in the profile folder ?

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 Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Yes. The file is there. And but I've just tested that even if I added a word to the dictionary (by right clicking on that wrong word), it doesn't show/get added to that dictionary.

Though that dictionary does show around 20 words, which I have/had added at some point of time.

Does Firefox accept words that are in the persdict.dat file as spelled correctly (i.e. they aren't flagged)?

I found that the word is appearing in the dictionary and also appeared as correct spelling here after.

But I'm sure that it worked for 1 or 2 testings only. I'm sure that I've added some more than 1000 words already. But my persdict only contains some 75 words. Where are others going?

Of course, I'll keep a more acute eye hence forward as which words particularly are eloping.

Also, when I add a new word, pls tell if it is supposed to appear on top or bottom or alphabetically? my Testtest appeared in no order in any of these 3 types.

New words should be added at the bottom of the list.

You can open the about:profiles page via the location bar to check whether multiple profiles are present and which profile Firefox currently is using.

• Do NOT click any Remove button on this page.
• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

Thank you, but I've checked that new words are, at-least, not getting added at the bottom. So it has become difficult to me which words are getting added, and which are not. Or which, once added, get auto-removed after a few days (may be when new words get added).

I've got only 1 profile. Sure about that.

Yesterday I added the new word 'Testtest', and saw that it was added somewhere it between. I noted the total number of words: 75. Also noted the 1st and the last word, 'pre' and 'bcd' Now 'pre' is still in the beginning. But 'bcd' has shifted from the last, 75th, to the around 11th position.

How can I keep track as to which words get added but get removed later. Pls help.

Use these links to create a new profile. Use this new profile as is. Is the problem still there?

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder

https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

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

Zopfan said

How can I keep track as to which words get added

Once the problem is solved, you can open the persdict.dat file in an editor and remove what you don't want.