When opening an existing model, the following error message is generated.
Close the model, but leave the program open. Next, go to Tools > Database Utilities > Compact Database and select the database file. Next, choose the selection to purge the database to save space. Once that is completed, try opening the model to see if that helps.
If that doesn't help, try moving just the .stsw and .stsw.sqlite files (for the storm-sewer products) or the .wtg and .wtg.sqlite files (for the water products) to a new folder location. At times, one of the supporting files can cause an issue when opening a model. Open the model from the new file location and see if the error occurs.
If moving the files doesn't help, try importing the database file into a new model file. To do this, go to File > Import > (program name) Database. For instance, if you are using SewerGEMS, you would choose "SewerGEMS Database". Select the database files associated with the model file. The database file will be imported into a new drawing. The database file contains all of the physical data in the model. The only thing that is lost during this process are data in the element symbology and graphs. If you have any background files, these will need to be added back in as well.
If the issue still occurs, see if you have a recent archived copy or a recent backup database file. The backup files will have file extensions similar to "stsw.01.bak" and ".stsw.sqlite.01.bak". This link has information on restoring backup files.
If these steps do not work or you do not have a backup or archived copy of the database, please contact Bentley Technical Support for further assistance.