Symptoms
You will see an error like the following.
Account "ACCOUNT_NAME": Insufficient disk space is available. "/home" on host "HOSTNAME" has 123.4 GB free and requires at least 234.5 GB free, which includes space for temorary files.
Description
This is due to non of the home directories having enough space for the transferred account. This space needs to be available on a single home directory and can not be split across home directories.
Workaround
You may be able to free space on one of the home directories by moving accounts to another.
How can I move an account from one home partition to another?
You can add a new disk to the server with enough space for the account.