Problem Description

I have modified a few custom DataGroup property values for my doors and windows by right-clicking on the component, choosing the Modify Component command, and changing the values as needed.  But after reopening the file a few days later, I noticed that those properties reverted to their original un-modified values.

Steps to Resolve

Assuming that you do have read/write access to the file and other elements can be modified as expected, it is possible that the DataGroup instance data applied to these doors and windows is not "in sync" with the DataGroup System itself, at the project/dataset level.  To resolve this difference:

1. Open the DGN file in question and choose Utilities > Building Designer Utilities > DataGroup Upgrade Utility (third item in the list).
2. Click the Update button; This will update the list of DataGroup properties assigned to each element in the file so that they align with the DataGroup properties and schemas stored within the project/dataset. 
3. Change the applicable DataGroup property values as needed. 
4. Save Settings. 
5. Close the file, exit AECOsim Building Designer and reopen the file.  

At this point the DataGroup property value changes should be retained.