To troubleshoot SCCM Task Sequences we use the smsts.log located on the SCCM client. Unlike other SCCM components, the size of the smsts.lg is not configurable in the registry.
Keep in mind that Task Sequences can run even before we get the SCCM client on a computer, so the above registry key might not exist. The SMS Task Sequencer log file is by default 1 MB in size. Sometimes that is not enough to troubleshoot task sequences. To increase the size of the smsts.log we need to create a smsts.ini file and put it in the Windows directory. The smsts.ini file should loook something like:
The above example makes the smsts.log 5 MB in size and we will keep one 5 MB history file. If you are booting up from media or PXE, you need to edit you boot image such that the smsts.ini file is in the Windows directory.