Xnotifier 4.0.3 Doesn't save account and repeats update message.

I'm using Xnotifier for Firefox, which is updated to the latest version (4.0.3). Everyday is erases the accounts, but I can't find the cookies to save either in Firefox settings or Ccleaner settings. Searching for "xnotifier" like some posts in other threads suggests yields nothing. Another bug is every time I start Firefox for the first time each day I get the update message as if a new version updated, but it hasn't since May 9th.

I might suggest trying to reinstall 4.0.3 (do you have a good export of your accounts?) to get rid of update message.
And don't forget... when defining accounts with versions 4.x, scroll down and click the Save button.

Yes, I have an export for my accounts probably from version 3.x.x. Also did the reinstall, now wait and see tomorrow.

Edit: Unforunately the reinstall didn't stop the update message from appearing.

For the persistent update tab, you might also try clearing your cache/cookiies... or specifically, "xnotifier" cookies.  Apparently the just-updated indicator is not being reset.

When I finish using my computer for the day, I run Ccleaner with cache and cookie cleaning under Firefox. Unless it's needed from Firefox settings too?

CCleaner is probably  clearing the X-Notifier 4.x update status cookie... you should add an exception  for "xnotifier" cookies perhaps.

That's the thing, Ccleaner doesn't find one in it's search for exception. Unless it's not written as  "xnotifier".

I'm running Firefox 53 with old X-N 3.5.23 and also Firefox Portable 53 with X-N 4.0.3.  
My CCleaner doesn't seem to pick up Firefox Portable, just my main Firefox...
...but if you go to Firefox, Tools, Options, Privacy, History, Use custom settings..., Show Cookies and search, you'll see xnotifier cookies.

Perhaps...
You might go to CCleaner, Applications tab, find Firefox and UNcheck Cookies...
...and you if you need cookie control in Firefox, you could go into Firefox Tools, Options, Privacy, History, Use custom settings..., and set the combination you prefer for cookies and exceptions.

I have the same problem.

I installed it on a clean machine. I use W10 and FF 64-bit

I have resolved the problem.

If FF remember history in FF then the information wil be saved.