I didn't notice that before and I made a test... Actually what happens is that my dimension "becomes invalid" which usually means that the object gets erased and then re-imported so the dimension has no meaning during this change, that's why we get this message.... I did get a warning...
However, I don't think you can get rid of this problem sinse Revit seems to completely erase the object and re-create it ... that makes the dim line without a reference...

Andrew,

We've been having this problem as well. We only noticed it around the time we upgraded to 2011... before then, for some reason, it didn't seem to be as much of an issue. I don't know if they changed something in how Revit deals with dimensions?

We notice it most when moving things with the "Disjoin" checkbox checked. Because 2011 changed the behavior that leaves that checkbox checked, it's easy for users to forget that it's still checked.

Disjoin REMEMBERING its setting is the worst nightmare ive ever seen someone at the Factory make.

Having said that, ive found 2011 to be BETTER about deleting dimensions then previous iterations. It now tells me its going to just remove references, when they are tied to Linked elements that change type, instead of telling me to delete the dimensions on the whole.

My money is on project team members using Disjoin and blowing the dims away unknowingly.

Yep. It's kind of ironic, because in general, everyone has been begging for the Factory to make more checkbox settings persistent (e.g. Mirror "copy"), and the first one they change is one of the very few that should never be persistent. Maybe it was done out of spite.

Hi. This is my first post. I found this site Google searching for this issue because I can't take it anymore. Thank goodness I'm not the only one with this problem. Since we started using 2011 dimensioning has been a nightmare! They are unruly to say the least. Whenever I draw something, dimension to it, and then move that element later, all the dimensions freak out and either become "unconstrained" or they simply vanish. It's annoying and counterproductive. That's with EVERYTHING from simple detail lines to model elements. It was not nearly as big of a deal before now. Does anyone know if there is any relief in the newest version? Thanks!

Have you checked to see if Disjoin is checked in your option bar when you are moving and altering things after dimensioning them?

Or if the Constrain is unchecked. This might also cause the dimensions to be lost.

Disjoin is the Devil's work!

The "Disjoin" was checked. That was the entire problem. Once I unchecked that box, everthing responded as it should. Thank you for the tip!

I too have been having this problem with rst2013 and have gone as far as trying it with the disjoin box checked and unchecked with the exact same result each time. The most frustrating part about it is that the changes that I've been making should have no affect on the dimension. This has happened with 2 different changes. The 1st was changing a wall thickness from 8" to 7" with either the interior or exterior face remaining in the same location prior to the change has caused me to lose wall length dimensions and any dimensions that may locate any openings that pass thru the wall. I've also created some beam pockets in the walls for beams that are continuous thru the wall only to not have the void extrusion stop cutting thru the wall, so that when I go into the assembly and edit the void extrusion so that it cuts the entire wall, I end up losing the dimensions that located the pocket along the wall.

Can anyone offer a suggestion as to why this is happening?