I thank  ClitheroeKid for his recent gracious help (as well as  ¡Firedog for past responses that continue to guide me.)  

My new question:Is it possible to combine Mail.MSMessageStore databases? Running a PC with Windows 10 Build 1909,my [overburdened] WML 2012 program has apparently created an additional backup folder with a subfolder called "2020-10-07-185859."

(The original Backup folder is present but has no Mail.MSMessageStore at this time.) It has only a few MBs of data (equal to the original number before I have [somewhat successfully] forced WML to create a new Mail.MSMessageStore by Importing corrupted Messages from a Desktop folder.Many Messages now in Storage folders can be read.)

Based upon my observations,they are NOT currently being utilized/contained in the Mail.MSMessageStore and there are some files I can no longer find/open that I was able to open even after my "overload,'' reported on an earlier thread.

Is it technically possible to ADD this data to the data now in Mail.MSMessageStore? If so,how?