How to prevent changing the assignee field to "unassigned"?

[Greg Ananev]

Hello there!

Guys, I need to prevent changing the assignee field to "unassigned" from View and Edit screen.
I mean I might be able change the assignee to some person, but not to unassigned.

It should be project-specific option.

Could you help me? Thanks ahead!

[Peter Bengov]

There is a Instance-level ability to do so: Administration > System > Allow unassigned issues.

Otherwise, you could use workflow validators & post-functions to make sure during transitions this isn't changed.

Another suggestion - you could use "generic" users instead to be auto-assigned. This will help prevent users from editing Assignee field.

[Greg Ananev]

Unfortunately, these solutions does not fit. Maybe there are any custom scripts to verify this condition? (I mean scripts for "script type" workflow conditions)

[paps eddy]

thanks for help @Peter Bengovits works for me.. 

[Peter Bengov]

Happy to hear, paps

Feel free to upvote the answer, for future generations :)