There are no task sequences available to this computer
We have experienced the issue for Unknown computers,
"There are no task sequences available to this computer. Please ensure you have at least one task sequence advertised to this computer"
As per below blog, this issue is fixed in 1702 update rollup
However, the issue still occurring after 1702 rollup fix.
Updating status to completed. This was addressed with our 1702 hotfix roll up.
We suggested to verify boot images were updated after applying the hotfix – the updated binaries need to be injected to the Boot Images, select the Boot Image, select Update Distribution Points will ensure the latest are added.
Yep 2 way I have seen this scenario clicking the previous button and just after a task sequence has been edited
Charles Kozakiewicz commented
yes we saw this in our environment, one of our techs clicked the back previous button and then continued the task sequence anyway. we had to delete the computer from the console that had stolen the GUID for the unknown x64 computer
where System_DISC.SMS_Unique_Identifier0 like '%' + '8230bfa4' + '%' /* x64 Unknown Computer */
or System_DISC.SMS_Unique_Identifier0 like '%' + 'd77712c0d' + '%' /* x86 Unknown Computer */