Similar to question already asked and answered. However, I saw that one earlier, so I already disabled all Add-Ins, closed Outlook, and ran Scanpst till "no errors". Then I restarted Outlook and tried again to "unsubscribe" from several of the "subscribed" IMAP folders. It acted as if it "took" the instructions, so I did Send/Receive again. It still took a long time, so I returned to the list of IMAP folders to check and found that it again shows that all of the IMAP folders are "subscribed."
What to try next to get some of these IMAP folders "unsubscribed" so my Send/Receive doesn't take so long?