The first time I used my "Restart MusicBee" button, most of my layout settings were reset to default (at least, I assume it's default). Specifically, the left and right sidebars, the thumbnail and column browsers, and the player panel were reset. The toolbar remained in the caption bar. Further resets seem to be fine. (I had also just canceled a sync when I used the restart command, if that matters.)
Also, sync settings didn't carry over from 2.5. Should they have?
Edit: Correction, it just happened again. I had been fiddling with the Sync settings, then removed a virutal device. I had run a sync preview, but not actually tried to sync. Oh, and my second virtual device, which I had not deleted, disappeared during the reset but reappeared when I made a new virtual device. Will add settings screenshots when I get them reconfigured...
(Aside: please make the sidebar player retain its settings after it is disabled and reenabled.)
It reset again after I created the new virtual device. (No attempt to sync or preview.) This time I had closed it and reopened it manually, and when I restarted I got this message:
MusicBee v3.0.5771.40637 (Win10.0), 21 Oct 2015 2:24:
System.NullReferenceException: Object reference not set to an instance of an object.
at #=qIsVYD9lEiC$UzQHc2vTJZ$Fx5C0LP0JNtREKWO2X9Cg=.#=qHBgk2QAzQPfYGRtDUXLeWg==(String #=qoF7x7bwx_eXvCVf2BQfuBQ==, Form #=quPiQ2H8GzlT2WOSLTfmR3Q==, ControlCollection #=qGhrp6_VgGkc8EzLmKzvZMQ==)
at #=qIsVYD9lEiC$UzQHc2vTJZ$Fx5C0LP0JNtREKWO2X9Cg=.#=qb4jsouLZldU7U5V60QzmrQ==(String #=qg9Nll2EKneolsQyI7zvJZw==, ControlCollection #=qNiP0JlX8C7vCORCUb9Zv8g==)
at #=quKhs69E8Lir$jr7iFgGHHBdOHLZEoyzRdV9P6hQno$J0bxNeVqIzCXtuG80SKbrE..ctor(#=qYiBrCwgabegamgJ6RCwiqIyJ6xpeOW0Qf3bcWsv_DNr2L2xxrNIDg_VZQ3j7DgCp #=qvv9b9S92ILiWo$$EpkA3jA==)
at #=qYiBrCwgabegamgJ6RCwiqIyJ6xpeOW0Qf3bcWsv_DNr2L2xxrNIDg_VZQ3j7DgCp.#=qGz3_la2lLtscMfuqV2s_wakX2EJMM8uzw3OWqhTptj4AKe_u3HfsOGA8q5lBC62M(Object #=qQ3b2f31TOVwrHx2TdQ1Swg==, EventArgs #=q2HByw3K6K1$jECHrfyfwsA==)
at #=qlMcsC5ixxwq5uFGLOu9aPXi9IWeIG1F3P2TMw6Jjypc=.#=qH2lCa8WlboOinvAnGrhesWPcg6xgq_0SdZdz5ZwPS5M=(#=q6nEWOBWBXstv$celfxy_llqlYD8BecHDOVNGHu$j7Vd$gbmZK$pkV4aW8j7CD0r$DKOiz7cyjnUNId8a7m2n5Q== #=qB2putbrZeg1OmLVU3X9w6g==)
at #=qlMcsC5ixxwq5uFGLOu9aPXi9IWeIG1F3P2TMw6Jjypc=.#=qq9AZw6Us58ROAyWwTg2uEQ==.#=qPh$n17PIeTOCALMXn_JYgPK0CsdmEQVyQE87e4WeMrU=(Int32 #=qZbKb6i7fchUAMoLgPxSSlw==, Boolean #=qFrdW4GgrAB3NLufzvcDUXw==, Boolean #=qXBo5qGc2AxIpLXsKwgb5alFJrWB9UWwzlALcFrmWzwk=)
at #=qlMcsC5ixxwq5uFGLOu9aPXi9IWeIG1F3P2TMw6Jjypc=.#=qq9AZw6Us58ROAyWwTg2uEQ==.#=qjFIJF$TG7RQxHJAsotOPTZlxdT7BtDk7KAaSsrwlhBk=(Int32 #=qtdrAkDa1envct9OzNZXwgA==)
at #=qlMcsC5ixxwq5uFGLOu9aPXi9IWeIG1F3P2TMw6Jjypc=.#=q7siwWk6f9oQrew8H8VycZ0KprmvQ98JnDX6fqVKxDmY=(Int32 #=qwb_$g5EkaBEIEsXisaSuPg==)
at #=qYiBrCwgabegamgJ6RCwiqIyJ6xpeOW0Qf3bcWsv_DNr2L2xxrNIDg_VZQ3j7DgCp..ctor(Point #=qUZBoN3ZBTeOdiEuyJiRf1Q==, Int32 #=qDrXcHavg2GHrF5uV$4UyyA==, Int32 #=qJyS7lvlF5RFEKXRDe3AXgw==)
at MusicBee.MusicBeeApplication.#=qe41YyKwMbBmEFc537uzLpg==.#=qvRU52mKTjVb_YZFJ2o_DPN9jfzrjQ3X2tIj9QDsMeD4=()
at MusicBee.MusicBeeApplication.#=quaNZnB_m9aA2Ydv3fRS5$Q==.#=qwGwYFpO3M$n$3gBq6kiOKw==(ApplicationCommand #=qd_vbRE4ZcrwvlUf82BfXqg==, Object #=qq0xLUZ1Q_Fyos_t7Hvo7LA==, IList`1 #=qRwb5A07GVHSA6GhRc4Hq1Q==)
at MusicBee.MusicBeeMain.NavigationHeader.#=q1QJQcxt3kLUINn9_5ymOVg==(MouseEventArgs #=qKKVpbFRoUQyS8vkUZRjcPw==)
at MusicBee.MusicBeeMain.OnMouseClick(MouseEventArgs #=qTshZbCc3_z8oF2cTn8tA1A==)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at #=qErDu_pdQdE263OPO0h6Hk1TXzslGZCCzs5vBfmuJn8E=.WndProc(Message& #=qfwwnxsVakcJBWcpbhKZ5Aw==)
at MusicBee.MusicBeeMain.WndProc(Message& #=qcWKB3vry1GvK8h8gyseSGQ==)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
I haven't gotten that error at any other point, but further testing reveals that even just navigating to the virtual device in the left panel triggers the layout bug. (If you think it matters, I can test with an actual, attached device, too.)
Here are the layout settings as I had them:
Here they are after reset:
(An extra curious point: even though it shows the column browser enabled in the main panel, it doesn't actually show up until I open and save the layout settings.)
p.s. this new layout configuration does make it really quick and easy to fix the problem!