Maybe the simplest option is just to reopen all of the tabs by TMT that you want to import, and then just save them again using the TO, by window save-close button, or by using the "save-close All Open Windows" button from the main toolbar.

If must be done only once, this is definitely faster than writing conversion script, even if need to reopen up to several thousands tabs.

After that, the Tabs Outliner tree can be exported in plain HTML by Ctrl-S in the TO view.

And from this exported HTML windows and hierarchies can be dragged back to TO View, without reopening them. This is actually one of the way how import data back (exist other ways, but not through the TO user interface).

But really, if this only the windows in other session manager, it will be much easy to just reopen all of them and save again in TO.

Well, if for true, i am highly doubtful that this is possible, knowing how the algorithm work.

But good to know.

Soon there will be update that will allow to navigate back in history, and see the tree at any point of the past. Hope it will further secure our precious tabs ; )

Nor even it can actually.

You can easily see same artifacts on a Chrome without installed TO or with disabled Tabs Outliner. That's how Chrome work. 

You can easily see same artifacts on a Chrome without installed TO or with disabled Tabs Outliner. That's how Chrome work. 

>  when Chrome crashes, is it 100% certain that TO would preserve all open windows? 

yes

>>> I just can't find a workable solution of preserving my session when i need to reset Chrome for whatever reason. >>>

Why not to use Save-Close All Windows button in TO for this (the main TO button actually, it is even carries TO logotype)?

Do you select the tabs outliner window before this?

Click somewhere in it before Ctrl-S.

You can also right click anywhere in empty place in TO window (or on buttons toolbar) and select Save As... from the context menu (but make sure you right click not on tabs but on empty space)

Yet Ctrl-S must work. Have no clue why it is not work for you.

You can also drag and drop root node in Google Doc or Word to export hierarchy.