FF Backup File not being Created

FF 154.0 will not create a backup file. Trying to create an initial backup to my D: drive (2 TB Samsung 990 Pro M.2 Gen 4 NVMe SSD with 86% free space). WIN Pro 25H2 Operating system, Intel Core i7-14700K CPU; 64 GB DDR5 - 5600 MHz Corsair Vengeance DRAM. No matter what I do I can't get the initial backup to complete even though the D:/Restore Firefox folder was created. I consistently get this message, “Hmm, there was a problem with the backup. Please try again in a few minutes.” The message result of browser.backup.backup-debug-info is: {"lastBackupAttempt":1787153673,"errorCode":9,"lastRunStep":13}