we get the message when trying to save a segment sometimes but the segment always seems fine if we re-open it.
and the segment manager is slow depending on the number of segments you have defined. For normal users it's pretty fast since they can only see their own segments and those shared with them. But as an admin you get to see ALL the segments in your login company.
The best thing to do (which I need to heed my own advise here) is to unshare segments that don't need to be shared with all and just share them with whoever needs them. Delete old crufty not used segments if you can. Overall general cleanup will make the segment manager run faster. Don't worry about cloud or data warehouse used segments. If you try to delete them you will get a warning message (and if you open the segment for editing it will tell you it's in the cloud or datawareouse and if you edit it you will break something). In that case leave it or make sure to make sure it's not used in Audience manager, target before deleting. But if you get down to just those segments your cleanup is probably complete anyway since the majority of segments are one-off segments that you don't even use anymore.
Of course it would be nice if there as a 'segment usage' report you could run to find out where segments are used in dashboards etc.
An overall segment cleanup could include tagging segments with tags like 'dashboard' or 'deletable' etc. Also setting them to 'approve' for those you know shouldn't be deleted (and actually work). Also editing the segments and adding a description helps.
