Hi,
Thanks for posting in Microsoft MECM Q&A forum.
1,Maybe it is due to corrupt task sequence. Please delete and recreate a completely new task sequence to have a try.
2,If possible, also restart the MDT server to have a try.
Similar threads for your reference:
How to: Microsoft Deployment Toolkit - No Task Sequences error
Error "No task sequences are available (TaskSequences.xml does not exist, is empty, or is inaccessible)"
Please note: The links are not from Microsoft, just for your reference. Thanks for your time.
Best regards,
Simon
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