Firefox 38 esr will not be updating as it was discontinued in June and you presumably had updates turned off or blocked, because otherwise it should already have upgraded back then.

It should be possible to install Fx45 esr. I imagine if Fx38 esr installs are turned on it would upgrade to Fx45 esr. You attached an error message about multiple Firefox versions being installed. You should ensure each Firefox version has its own Firefox profile. (You can clone or migrate profiles if necessary)

This old article may help with sorting out the updates

• Updates reported when running newest version_delete-update-configuration-files

Both versions were available simultaneously for a twelve week period in order to allow testing out of Fx45.0 & 45.1 before needing to discontinue Fx38.7 & 38.8

If you are getting Firefox Crashes then it may help if we know the Crash IDs

• Troubleshoot Firefox crashes (closing or quitting unexpectedly)

That may however be a separate matter, as Firefox crashing indicates it is installed.

Thanks for the response John99. Firefox 45.5.1 is installing update 45.6 now but each user has to open and close firefox 2 to 3 times before the update takes. Not sure why its doing this there are no other versions installed because I have deployed a script to remove all previous versions then install Firefox 45.5.1.

Not sure I understand what is happening, but it may well just be the normal release procedure.

The release process is sometimes throttled. Typically not all users will get updates then after a certain threshold of numbers of upgraded users is passed the automated updates are not immediately offered. That allows time for a review to see if any major problems are seen; and if they are updates may be suspended; if not then they may be unthrottled and offered to all

Usually if an update is available then if a user specifically clicks on the

Menu Button {3 bar icon) -> Help ((?) icon) -> About Firefox 

That should force an update assuming one is available.

There will not be much difference between Fx45.5.1esr & 45.6.0 they will both be for back ported critical security updates Release Notes

• 45.5.1
• Version 50.1.0, first offered to Release channel users on December 13, 2016
  • https://www.mozilla.org/security/known-vulnerabilities/firefox-esr/#firefoxesr45.5.1

Sorry but personally I only use the ESR versions for test and comparison purposes and do not follow details of the Release progress. Your best source of information may be subscribing to the EWG mailing list (see)