I see lots of administrators struggling with this error especially when they replace an HDD on a machine and then try to re-image it. Task sequence has failed with the error code 0x800700A1 is an error that also come up when you’re imagining a brand new Virtual Machine.
What does the error mean? 0x800700A1 means BAD_PATHNAME. The reason why you get this error, most of the times, is due the fact that the task sequence isn’t able to find the path because the drive is RAW.
In order to fix this you will have to initialize and format that Hard Drive. If you are in the SCCM’s WinPE environment, simply press F8 to get to the command prompt and type the following:
SELECT DISK 0
CREATE PARTITION PRIMARY
SELECT PARTITION 1
FORMAT FS=NTFS QUICK
ASSIGN LETTER C