Migrating user IMAP files/data to another hard drive/server

Due to a machine crash, I need to move my mail server to another host. This includes user IMAP, but as the old server is not accessible I can't just drag and drop in an imap client application like Thunderbird. Rather, I have the old hard drive, and am trying to move the file structure to the new /home partition. I have not yet had success. I have copied (cp -pr) the old file structure wholesale onto the new server/drive. However, the imap client isn't recognizing the old folder structure or the old messages anywhere but the inbox. The file structure has a '~mail' directory under ~home, and in that are the folders containing the email. What do I need to copy, and where, to ensure that the users can access their imap data on the new server? Running CentOS 8 with Sendmail and Dovecot. [spamtrap_003@davinci ~mail]$ ls -la total 90496 drwxr-xr-x. 4 spamtrap_003 spamtrap_003 4096 Dec 8 14:05 . drwx------. 6 spamtrap_003 spamtrap_003 213 Dec 8 11:46 .. -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 562 Apr 5 2013 Carolingia -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 620 Jun 8 2014 'Deleted Messages' -rw-r--r--. 1 spamtrap_003 spamtrap_003 580 Dec 8 14:05 dovecot.list.index.log -rw-r--r--. 1 spamtrap_003 spamtrap_003 24 Dec 8 14:05 dovecot.mailbox.log -rw-r--r--. 1 spamtrap_003 spamtrap_003 8 Dec 8 14:05 dovecot-uidvalidity -r--r--r--. 1 spamtrap_003 spamtrap_003 0 Dec 8 14:05 dovecot-uidvalidity.61b101e2 -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 6672436 May 25 2021 Drafts -rw-r--r--. 1 spamtrap_003 spamtrap_003 6902202 May 24 2021 Fitbit -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 639800 Dec 8 12:45 ham drwxrwxrwx. 20 spamtrap_003 spamtrap_003 4096 Dec 8 14:06 .imap -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 149895 Nov 20 2014 PSL.iPad -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 28823 Jan 21 2013 Rayburn -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 195356 Sep 10 2014 RenStore -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 6245982 May 25 2021 Sent -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 45228 Oct 12 2015 'Sent Messages' -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 71725052 Aug 17 08:51 spam -rw-r--r--. 1 spamtrap_003 spamtrap_003 102 Apr 9 2021 .subscriptions -rw-r--r--. 1 spamtrap_003 spamtrap_003 11 Dec 8 14:05 subscriptions drwxr-xr-x. 6 spamtrap_003 spamtrap_003 121 Dec 8 14:06 .Trash -rwxrwxrwx. 1 spamtrap_003 spamtrap_003 603 Apr 13 2021 Trash The .imap subdirectory shows as follows: [spamtrap_003@davinci .imap]$ ls -la total 28 drwxrwxrwx. 20 spamtrap_003 spamtrap_003 4096 Dec 8 14:06 . drwxr-xr-x. 4 spamtrap_003 spamtrap_003 4096 Dec 8 14:05 .. drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 Carolingia drwxrwxrwx. 2 spamtrap_003 spamtrap_003 6 Dec 8 14:05 cur drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 'Deleted Messages' -rw-rw-rw-. 1 spamtrap_003 spamtrap_003 40 Dec 8 14:05 dovecot.index.log -rw-rw-rw-. 1 spamtrap_003 spamtrap_003 3748 Dec 8 14:06 dovecot.list.index.log -rw-r--r--. 1 spamtrap_003 spamtrap_003 24 Apr 9 2021 dovecot.mailbox.log -rw-rw-rw-. 1 spamtrap_003 spamtrap_003 51 Dec 8 14:05 dovecot-uidlist -rw-r--r--. 1 spamtrap_003 spamtrap_003 8 Apr 9 2021 dovecot-uidvalidity -r--r--r--. 1 spamtrap_003 spamtrap_003 0 Apr 9 2021 dovecot-uidvalidity.607089eb drwxr-xr-x. 2 spamtrap_003 spamtrap_003 31 Dec 8 14:06 dovecot-uidvalidity.61b101e2 drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 May 3 2021 Drafts drwxr-xr-x. 2 spamtrap_003 spamtrap_003 58 Apr 9 2021 Fitbit drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Apr 11 2021 ham drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Aug 25 17:08 INBOX drwxrwxrwx. 2 spamtrap_003 spamtrap_003 6 Dec 8 14:05 new drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 PSL.iPad drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 Rayburn drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 RenStore drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Aug 26 08:11 Sent drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Mar 26 2019 'Sent Messages' drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Aug 17 08:40 spam drwxr-xr-x. 2 spamtrap_003 spamtrap_003 31 Dec 8 14:06 subscriptions drwxrwxrwx. 2 spamtrap_003 spamtrap_003 6 Dec 8 14:05 tmp drwxrwxrwx. 2 spamtrap_003 spamtrap_003 79 Jul 5 22:30 Trash Could it be the *permissions* on the Dovecot index files? The old and new both use Dovecot. I don't have the version for the old one; when it was running it had CentOS 7, fairly well updated. The new one is 2.3.8. The configuration for storage and mail folder type should be the same: {mail_location = mbox:~/~mail:INBOX=/var/spool/mail/%u} The new and old users are not necessarily the same (UID and GID), though the names match. I have, for one box, changed the owner for all files in and under $HOME/~mail to be owned by that user, to no avail. EDIT 13Dec21: I have determined that it is NOT a permissions/ownership problem. I was able to create a new folder via my imap client (Thunderbird), and it showed properly. I then examined the ownership and permissions of the created files and directories and duplicated them in an existing folder. This did not work; the folder still wouldn't show. Next is examining and possibly doing surgery to the actual dovecot index files that are created, since clearly it's not like I'm going to lose anything more. But wait. there's more. After collapsing and reopening the account's folder tree in Thunderbird, the new folder is no longer visible. Needless to say, neither are any old ones. I cannot discern why one account shows properly and the rest don't.