What happens when moving a task in the task list?

[Per_Alm]

Hi,
Sorry for a "stupid" question from a newbie: Tasks can be drag and dropped in the task list. When doing this they will change their task-ID to the new number of the row. In addition, also other tasks in the list will get updated task-ID. However, the number of the linked predecessors are not updated, which I guess means that the linking may become corrupt (if the predecessor got a new task-ID).

Yet, the start and the finish dates of the tasks remains intact, which also is confusing. If the links have changed the start dates would change.

I feel that I am missing some obvious point here... Someone?

Best, Per Alm

[#2 · Accepted solution]

Per_Alm --

Using drag and drop to move tasks will not cause any harm in your projects. I have used this technique for decades without a problem. Yes, when you drag and drop tasks, Microsoft Project DOES renumber the tasks. However, what you probably do not know is that there is a hidden ID number that DOES NOT ever change, which is called the Unique ID. Insert that column and then try drag and drop. Microsoft Project uses the Unique ID numbers to maintain the task links. Hope this helps.

[#3]

Thanks a lot, this explain things! I was thinking that the ID number should be unique, I was not aware that there was an additional "unique ID". And, I now noticed that I was wrong: the non-unique predecessor number does update, it was just that my test moves did not require updates. Thanks Dale!

[#4]

Per_Alm --

What a nice response, my friend! You are more than welcome for the help. BTW, if my reply answers your question, would you please mark my post as the best response? Thanks!