Opening old StormCAD .STM or SewerCAD .SWR files

 Applies To 
SewerGEMS, CivilStorm, StormCAD, SewerCAD
 Version(s):CONNECT Edition, V8i
 Original Author:Scott Kampa, Bentley Technical Support Group


How can I open an old .STM or .SWR file in SewerGEMS, CivilStorm, StormCAD or SewerCAD?


StormCAD version 5.X (circa 2003-2007) used a .STM file format and SewerCAD 5.X used a .SWR file.

For versions greater than CONNECT Edition Update 4 (, released in March of 2023), these files can no longer be directly opened. You will need to first open them in an earlier version (CONNECT Edition Update 3 or earlier) or contact Technical Support to convert the models.

For CONNECT Edition versions up to Update 3 ( - These models can be opened directly from the file open dialog in the CONNECT Edition of SewerGEMS (.STM and .SWR), CivilStorm (.STM), StormCAD (.STM) and SewerCAD (.SWR).

For earlier versions such as V8i, you may not be able to open the .STM or .SWR file directly (they may not appear in the list of available file types) and you will need to upgrade to CONNECT Edition.


Non-Bentley .STM or .SWR files

Other non-Bentley applications may use the file extensions .STM or .SWR and you will not be able to open those models as the Bentley/OpenFlows software only supports opening STM files from older StormCAD versions and SWR files from older SewerCAD versions (5.X circa 2006). One symptom of attempting to open a non-StormCAD/SewerCAD STM or SWR file is:

"Unable to load Project version"
"Jet Error #3265 item not found in this collection"

For example: Opening a WinStorm .STM file
"Storm Sewers for AutoCAD" is also known to use the STM file format.

To open such an unsupported file, you would need to contact the other software vendor to see if it is able to export to a format supported by the OpenFlows product. From the File > Import menu you can see that StormCAD, SewerGEMS and other OpenFlows products supports importing LanmdXML, MX Drainage, Inroads or MicroDrainage. If the other software vendor product is able to export to one of those formats, you will be able to then import.

Another option supported by the OpenFlows products is shapefiles. If the other software vendor product can export the network to Shapefile format, you can use the MdoelBuilder tool to import the Shapefiles to create the pipe network.

"Database format not recognized or read-only" error

When attempting to open the .STM or .SWR file, you may see the error "Database format not recognized or read-only. It could not be opened.".

First if the file type is not displayed in the file open dialog, type in the full path to the file in the box next to it. For example "C:\Examplefolder\exampleoldfile.swr". Alternatively, you can drag and drop the SWR/STM into the product window.

If this does not help, try opening the 32-bit version of StormCAD, CivilStorm, SewerGEMS, or  SewerCAD. You can find this by going to "C:\Program Files (x86)\Bentley\StormCAD" (or \SewerCAD for SewerCAD) and double-clicking on the StormCAD.exe or SewerCAD.exe file. You can also create a shortcut by right clicking on the StormCAD.exe file in the program files folder and choosing "Send to" > Desktop.

Once this is open, go to File > Open and select the .STM or SWR file (or drag-drop the file, if the STM/SWR file extension does not show in the file open dialog). Once the model file is saved in the current format, you will be able to work on the file in either the 32-bit or the 64-bit version.

If this still does not work or if you're encountering a different error when attempting to open the file, try upgrading to a newer version or contact technical support.

"A non-continuable protection violation has occurred" error

When opening an old StormCAD model (.stm file) you may see the error "A non-continuable protection violation has occurred".

Here are a few things you can try to resolve this issue:

1) Uninstall the old version

2) Copy only the .stm file, to a new, empty folder on your local hard drive. Sometimes network communication (if stored on a network share) or supporting files such as .rpc files can interfere with the upgrade.

3) Check to make sure that DEP is not enabled for StormCAD (Control Panel > System > Advanced > Performance Settings)

4) Try temporarily closing any third party running applications such as Antivirus, anti-malware, video card control panel, etc...

5) Upgrade to a newer version of StormCAD

"Value Not Understood" error

This may be due to a problem with the network such as orphaned nodes or disconnected elements. In order to fix this, you may need to access version 5.6 (for example on a Windows XP virtual machine), open the model, use the "check data" command to find issues, address those issues, re-save the file in V5.6, then try opening it again. If you do not have access to version 5.6, Bentley Technical Support may be able to help (consider posting on the forum and provide a zipped copy of the model using this information).