It seems that the backup process is almost complete but stuck at 99%. One suggestion would be to try waiting for a little longer as it might be just a delay. If it remains stuck for an extended period, you can try restarting the backup process or restarting your computer. It could also be helpful to ensure that there is enough space available on the portable HD drive for the backup. If the issue persists, seeking assistance from Acer support or referring to the program's documentation might be a good idea.
