Problem

The following error message is observed in the update log while trying to upgrade from SecureTransport 5.2.1 (any service pack) to 5.2.1 Service Pack 7 (possibly affecting upgrades from older versions to 5.3.1 as well):

ERROR Exception on com.axway.st.sustaining.patch.custom.impl.ObsoleteFilesRemover.onBeginningUpdate(): null Reason: java.lang.NullPointerException

Resolution

The cause for the error is a missing <FILEDRIVEHOME>share/ftdocs/html/skin/ric/C folder. This can happen when an HTML template was replaced with a custom one, or is using a non-default template folder path, or restore of incomplete/corrupt backups of <FILEDRIVEHOME>.

To fix the issue, restore the ST instance to a working condition (backup of the previous version) and either recover the original <FILEDRIVEHOME>share/ftdocs/html/skin/ric/C folder or create a new empty one.