Hello vinkpunt, with closed firefox (via firefox button > Exit) delete the downloads.sqlite file in profile folder and check it again.

see for more info : Downloads not visible in Download Manager

thank you

Thanks ideato for your suggestion. I had already tried that, but I've just tried it again. It doesn't make any difference, the problem is still there.

go to about:config and reset (right-click and select reset) the next preferences :

browser.download.dir

browser.download.downloadDir

browser.download.folderList

browser.download.lastDir

browser.download.useDownloadDir

if the above did not help, delete the prefs.js file in profile folder

thank you

I cannnot find a prefs.js file. There is a prefs and a prefs-1 file only. Should I delete any of those, or both?

"prefs-1.js" file include a missing setting (in case you want to recovering lost settings), delete it also(and prefs.js).

Now that created a chaos, deleting the prefs files! I have immidiately put them back! I guess I'm gonna have to get used to this badly functioning download manager. Thanks for the help anyway, Vincent from Holland.

Note that there should only be a prefs.js file (Windows hides the .js file extension) and not a numbered prefs-##.js file.
The presence of a numbered file indicates there there has been a problem with creating/updating prefs.js at some time and you can remove the numbered prefs-1.js file.
If the main prefs.js doesn't have a current time stamp then you will have to delete that file as well and redo all customization settings in Options.

Make sure that you do not run Firefox in (permanent) Private Browsing mode.

• https://support.mozilla.org/kb/Private+Browsing

• Tools > Options > Privacy: Use custom settings for history
• Deselect: [ ] "Always use private browsing mode"

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode

Thanks cor-el! First I have deleted the prefs1 file, but that didn't help, altough it caused no damage either. Then I removed the downloads.sqlite once more, but that made no change. I checked if I was perhaps in private mode, but I wasn't. So then I followed your last suggestion, the Firefox safe mode, and yes, that was it! Now my download manager was operating properly again! So it has to be one of my add-ons. Since I've only added one add-on recently, it has to be that one; Adblockplus. Thanks a lot for your help from Vincent, Holland.

Turned out to be the Ant Video Downloader (latest version) itself that caused the problem. So it's waiting for a new version of that and hope that will function properly again. Vincent.

Ant.com has solved the problem. A new version of the Ant Video Downloader is available! Vincent.