0.86: Cached thumbnails lost when opening the second instance

[rmtk]

When I opened a second instance of XnviewMP (showing only the base path of my pictures), close both instances, and then restart one, I saw the long list of cached directories in cache maintenance windows were all gone.
The Thumb.db and Xnview.db seem to be untouched, but XnviewMP no long recognise them and all thumbnails need to be rebuilt.

[xnview]

could you send me your xnview.ini?

[rmtk]

I changed several settings of XnView these days, and now I can no longer reproduce the bug...