Error message "Finish cannot be before start" appers while creating new activity in the Plan.

[RS_10651823]

I am using Windchill ProjectLink Release 12.0 and Datecode with CPS 12.0.2.13

We are getting the error message "Finish cannot be before start" while creating new activity in the Plan. The most probable cause of this we think is the Actual Start Date of the Parent Activity of the new activity we are trying to create but we wanted your help to understand what the actual cause of the error is and also for a particular activity when is the Actual Start Date attribute is populated.

Here are the errors that I faced
Finish cannot be before start

[avillanueva]

This appears to be a bug. SPR has been filed:

https://www.ptc.com/en/support/article/CS397068?source=search

Issue was not corrected in CPS9. Seems like this issue has been around for a while.

[cgautier]

Hello RS_10651823,
You encountered unexpected behavior while using Windchill, thanks for reaching out, this is Charles from PTC Technical Support in Europe.
Did you check existing kb articles ?
ptc.com/en/support
KR,
Charles.

[RS_10651823]

Hey, I did check the article and opened a PTC case with respect to this. The issue seems to be with the Actual Start Date as the error occurs while creating child for an activity having Actual Start date set. A work around was suggested to set the Actual Start Date to null before inserting a new child but currently I am unable to set the Actual Start date to null for any summary activity or Phase. I still have the case open for that and waiting for the response.