Hi New987,
I understand that you want to migrate emails to a new mailbox in the same Outlook profile. If this is the case, I recommend you a more efficient method to move emails between accounts.
First we back up Outlook data:
1. In Outlook, click File> Import and Export.
2. In the Import and Export Wizard dialog box, do the following:
a. Under Choose an action to perform, select Export to a file, and then click Next.
b. On the Export to a File page, select Personal Folder File (.pst), and then click Next.
c. On the Export Personal Folders page, under Select the folder to export from, select Mailbox -<user name>. Select the Include subfolders check box, and then click Next.
d. On the Export Personal Folders page, in the Save exported file as box, note the location where the backup.pst file will be created. By default, it's C:\Users\<user name>\AppData\Local\Microsoft\Outlook\backup.pst. Under Options, select Replace duplicates with items exported, and then click Finish.
e. On the Create Microsoft Personal Folders page, click OK to create a .pst file. If you want, set a password to protect the .pst file, which will be named backup.pst. A password isn't required.
Then move the data to another account:
1. In Outlook, click File, and then click Import and Export.
2. In the Import and Export Wizard dialog box:
a. Under Choose an action to perform, select Import from another program or file, and then click Next.
b. On the Import a File page, select Personal Folder File (.pst), and then click Next.
c. In Import Personal Folders, under File to import, locate the backup.pst file you created. Under Options, select Replace duplicates with items imported, and then click Next.
d. In Import Personal Folders, under Select the folder to import from, select the top node. Select Include subfolders, select Import items into the same folder in, and then select the top node of your mailbox (Mailbox - <user name>). Click Finish.
If you need further help on this issue, please feel free to let me know.
Thanks,
April Zhou