Now all of my saved groups are gone about tabgroupsmanager HOT 13 OPEN

Reloading the 2013.04.10 version and then restarting Firefox TWICE restored by 
saved groups.  I tried all of the betas, and none of them would find or restore 
my saved groups, so they are useless to me.  The remaining problem with the 
2013.04.10 version is that any tab added to any group is simultaneously added 
to all groups, which makes it very difficult to ever save a new set of groups 
(because all of the groups will have a large number of wrong tabs inside of 
them).  I see that this duplicate tab problem is solved in the latter betas, 
but those betas do not work for me for the reasons stated above.

Also, restoring manually saved sessions now does not work at all.

By my last comment, I mean that restoring manually saved sessions now does not 
work at all in 2013.04.10.

Also, deleting a tab from one group deletes the same tab in all groups.

In addition, now when I click on any tab, the page does not load until I hit F5 
to refresh it.

Disable all other addons and check result. Enable the addons step by step.

Also, saving a session does not work.  If a newly-saved session is loaded, what 
appears are the tabs that existed prior to Firefox 35.

This is really strange danmeek. Have you ben able to export your tabs to a TGM 
tmg2 session file? (with Save session or Export Session)
You should be able to import that session easily with the lastest 005 beta 
version.

It would be nice if you could try to import that session with your thounsands 
of tabs in a new firefox clean profile, so you could easily try if there is an 
addon breaking the cmpatibility with TGM.
You may start a new Firefox profile adding a switch to the process. In example:
F:\w7_programs\firefox\firefox.exe -p "musik" -no-remote

Please test it and report, thank you.

Saving the session does not work.  I save the session.  I restart FF.  I then 
restore the last saved session.  The result is the same set of tabs I saved 
prior to updating FF from 28 to 35.  I cannot save or restore any changes to 
the tabs since then.  I will try a new profile and report back.

Also, you may be not understanding the problem.  I am describing problem with 
using 2014.04.10 with FF 35.  As explained above, the betas, including 005, 
have other problems that make them for me unusuable in FF 35.  Namely, the 
betas cannot find or restore my saved groups at all.

So I loaded an entirely clean FF 35 profile.  I installed Beta 005.  That 
provided me with no menu items either to save a session or restore a session.

So I installed 2014.04.10.  I made a few tabgroups, using TGM.  I saved the 
session.  I restarted FF 35.  I selected the manually saved session to restore. 
 Nothing was restored.

Thus, I find that no version of TGM works with a clean FF 35 profile.

I do not know how to import my old tabgroups into the clean FF 35 profile.  
But, since the clean FF 35 profile cannot save any new tabs or tabroups anyway, 
that exercise would be futile.

As for "importing a session," that does not appear to be possible.  While the 
TGM menu structure allows exporting a session, there is no corresponding choice 
to import a session.  Nor is there any such choice in the settings menu.

That provided me with no menu items either to save a session or restore a 
session.
-> on clean profile the option to show the session menu is to activate in tgm 
options

The result is the same set of tabs I saved prior to updating FF from 28 to 35
-> this is a indication you have corrupt data in sessionstore.js and your tgm 
files.

Forget you old session, import, export and so on. There is only one way. Save 
your groups to bookmarks.

Then delete all groups in firefox, but this is not sufficient, because we 
suspect corrupt files, we have still to delete sessionstore.js & 
sessionstore.bak & sessionstore backup folder & tabgroupsmanager folder in 
profile where the .tgm files lives. Backup of fx profile before such operations 
is self understanding.

Its important that, if you delete the mentioned files the firefox is closed. If 
this is not the case firefox would write his old sessionstore file again on 
next close.

If all is done start firefox and open our bookmarkgroup as new group.

I figured out how to get Beta 005 to save and load sessions.  I had to 
right-click to the right of the group tabs rather than on the arrow to the left 
of the group tabs, as had previously been the case.  Now Beta 005 with FF 35 
appears to save sessions and load sessions.  Problem solved.