Resolving a "Backup Failed..." Sector Size Error.

When restoring data from a backup file Acctivate’s Database Maintenance tool, the following error may be returned:

Backup failed for Server '....' --> System.Data.SqlClient.SqlError: Cannot use the backup file 'C:\Program Files (x86)\Acctivate\Database\MSSQL15.ACCTIVATE\MSSQL\Backup\Acctivate$....bkf' because it was originally formatted with sector size 512 and is now on a device with sector size 4096.

This error occurs when you attempt to create a SQL database backup set on a computer that has a different hard disk sector size than the backup sets in the backup file.

While uncommon, this may happen after a database migration when attempting to backup on the  new server the first time, creating a new backup set in the backup file from the old server.

This is SQL Server doesn't support sets with different sectors sizes in the same file. To resolve this, rename the existing backup file and then run a new backup. 

Renaming the existing backup file will ensure previous backup files (created with the old server's sector size) will be preserved while allowing you to create a new backup file based on the new server's sector size.

Microsoft has additional information about this message and scenario on their knowledge base.