Resolve SOLIDWORKS PDM Add-In Error

A common SOLIDWORKS PDM add-in error is "failed to extract add-in from (path to add-in .CAF) class not registered." This error could be specific to the user, the vault, or that specific add-in. This article describes steps to take to either determine the nature of the problem or how to resolve it.

How PDM Distributes and Registers Add-ins on Clients

Each client must download and register the add-ins installed in their PDM environment to effectively run those add-ins or any tasks based on them. This is done the first time a user logs into the vault view, any time there’s an update to the add-ins, and when necessary files/registrations are missing.

This is the usual process an add-in follows from creation (or update) to the client:

1. An add-in is added to the Administration tool, either as a new add-in or as an updated version of an existing add-in.
2. The database creates an entry and a unique ID for this add-in.
3. The add-in DLL file is added to the archive on the server under the “…0\Plugins\...” folder under a subfolder matching the unique ID.
4. As each user logs into the PDM vault view, the database checks the version of the add-in that the client currently has. If the client doesn’t have one, or if the version doesn’t match, it then grabs the add-in DLL file from the server to send to the client. The files are extracted under the user’s Windows local application data folder: C:\Users\[USERNAME]\AppData\Local\SOLIDWORKS\SOLIDWORKS PDM\Plugins\[VAULTNAME]
5. Once they’ve been cached locally on the client, the system attempts to register these DLL files so they’re ready for use.

Potential Causes and their Solutions

When this distribution process is interrupted in some way, an error will occur like the one shown above. There are a number of ways the process can be interrupted, so let's go through some of the most common causes and how to troubleshoot them.

Distribution

A good place to start checking the cause of this issue is to confirm whether the files are even making it to the machine from the server. If the files don’t make it over, then troubleshooting on the client machine for prerequisites and permissions won’t matter.

In File Explorer, browse to the folder path listed in the error: C:\Users\[USERPROFILE]\AppData\Local\SolidWorks\SolidWorks PDM\Plugins\[vault name]\{CLSID}

If it’s distributing correctly, there should be one or more *.dll files and sometimes a .CAF file inside that folder. If the folder is blank, this is likely an issue with the archive distributing files to clients, and not an issue with the add-in itself. Check the local PDM logs to see why the client could not get the file from the Archive server.

Manual Registration

If the file exists, try registering it manually. Sometimes the registration process can fail, but a manual re-try will succeed. Be sure to take a screenshot or write down the file path indicated in the error message.

1. Open Windows Command Line by searching “CMD” in the Start menu. Be sure to run it as an administrator.
2. Type the following into the command line and hit enter: regsvr32 "C:\Users\Username\ AppData\Local\SolidWorks\SolidWorks PDM\Plugins\[vault name]\{CLSID}”
   1. Replace the text in quotes with the exact path from the error.
3. A pop-up should appear indicating whether the registration succeeded or failed.
   1. If it succeeded, reboot the computer and test once more by logging into PDM.
   2. If it failed, the error may provide some insight as to why.

Missing ADDINREGSRV64

If you’re repeatedly getting this specific error, instead of or in addition to the one shown above, it may be due to a recent install/upgrade missing necessary components for PDM. The Windows installer may have failed to register the AddInRegSvr64 class on the client, which would disrupt most/all add-ins rather than just one.

1. To identify the installation folder for PDM, open the Registry Editor. You can do so by searching “regedit” from the Windows Start Menu.
2. Browse to: HKEY_LOCAL_MACHINE\SOFTWARE\SolidWorks\Applications\PDMWorks Enterprise
3. View the path called out in the Location string value:
   
   
   
   
4. Open Windows Command Line by searching “CMD” in the Start menu. Be sure to run it as Administrator.
5. Type the following and hit enter: CD “[PATH]”
   1. Replace [PATH] with what shows under the Location string value in the Registry Editor that you found in step 3.
6. Type the following and hit enter between each line:
   
   regsvr32.exe /u EdmInterface.dll 
   regsvr32.exe EdmInterface.dll
   AddInRegSrv64.exe /unregserver
   AddInRegSrv64.exe /regserver
   
   
   
   
7. This should have unregistered and registered the API library and the class for that DLL. When done, reboot the computer.

Version Mismatches

Sometimes the add-in has been updated to the server, but for some reason the mismatch isn’t triggering a refresh of the cached add-in (or it’s being interrupted) on the client.

First, make sure that your add-in is up to date (ensure the version of the add-in matches the version of your PDM environment). The first 4 numbers of the add-in represent the year and service pack. The rule is to take -8 off the first two numbers to get the actual year (i.e., 3303 for the Dispatch add-in below). [33 = year, 03 = service pack]. 33 – 8 = 25. So, you’ve got 2025 SP03. This should be the same version and SP as your PDM version.

Add-in version via the Administration tool:

Installed PDM version:

Note: If you have multiple vaults on the same machine and they use the same add-ins, the shared add-ins must be on the same version, as PDM will only be able to download and register one copy per add-in.

If the add-in version doesn’t match the PDM version, upgrade it to match. If it does match, try manually triggering a cache refresh.

Cache Refresh

There are instances where either the download or registration of the DLL files fails, causing subsequent error messages to prompt when accessing the vault view. Clearing the AppData folder will force your system to re-download and register a fresh copy of the DLL files in question.

1. Close the Administration tool and exit PDM from the system tray, if active (click the blueberry icon > exit).
2. In Windows File Explorer, browse to the following location: C:\Users\[USERPROFILE]\AppData\Local\SolidWorks\SolidWorks PDM\Plugins\[vault name]
   1. You may need to turn on hidden items in File Explorer to see the AppData folder, as it’s not visible by default.
3. Delete all folders within this location.
4. The folders are named after an add-in’s CLSID, which is a unique identifier used by the system to differentiate each one. The naming convention will be curvy brackets containing several strings of letters and numbers separated by dashes.
5. Log back into your PDM vault view and then right-click anywhere in an empty spot in the file list to begin the add-in registration. The client computer retrieves the vault add-ins from the archive server, creates folders with the GUID of each add-in, and then extracts the add-in DLL and registers the DLL file.

Occasionally, refreshing won’t work unless you reboot the machine at least twice. If an add-in has been replaced, it is possible that the older add-in DLL is loaded before it is replaced, which means the older add-in will still be in use. Rebooting the client workstation multiple times will ensure the updated add-in is loaded.

Prerequisites

If an add-in relies on certain prerequisite programs and frameworks to function, missing those may prevent it from functioning on the client. The two main prerequisites we see pertaining to add-in issues are .NET and C++.

.NET FRAMEWORK 3.5

Windows 10 and Windows 11 operating systems only enable .NET Framework 4.5 by default, whereas .NET Framework 3.5 is optional. Many add-ins are still built with .NET Framework 3.5 or earlier, however, so you’ll need to enable it.

1. Go to Control Panel and then select Programs and Features.
2. Select Turn Windows Features on or off (you will need Windows Admin rights to do this).
   
   
   
   
3. Check the box next to NET Framework 3.5 (includes .NET 2.0 and 3.0) and click OK.
   
   
   
   
4. Restart the computer.

VISUAL C++

PDM should install C++ by default, but if this was missed for some reason, you can install it manually.

1. Navigate to the PreReqs folder in the installation files for your version of PDM.
   1. The default is “…\Documents\SOLIDWORKS Downloads\SOLIDWORKS 20XX SP0X\PreReqs\”, but you may have placed it elsewhere.
2. In the PreReqs folder, you should see one or more “VCRedist##” folders, where ## corresponds to a version.
3. Run all “VC_redist.x##.exe” files under all VCRedist## folders.
4. Restart the computer.

Conflicting CLSID Registrations

Most add-ins, including the default add-ins included with PDM vaults, are COM-based add-ins. A COM add-in is a supplemental program that integrates with a “host” software to extend its functionality rather than a standalone application. Each add-in has a name and an associated CLSID (or class ID) used to identify it. The CLSID is the long string of letters and numbers inside curvy brackets often seen in the add-in errors.

The system uses the Windows registry to link up an add-in’s CLSID to the correct version so it knows which files and calls to use to function. If you’ve upgraded PDM or have multiple vaults using the same add-ins, you end up with several pointers in the registry for a single CLSID, making it so that PDM can’t identify which one it should be using.

To fix this, start with the same steps as the Invalid Cache section above and clear out the existing add-ins on the client:

1. First, screenshot or write down the CLSID you saw in the error.
   1. If there’s a number after the end bracket, like the 3 at the end here, ignore it. The CLSID will be whatever is inside the brackets.
      
      
      
      
2. Close the Administration tool and exit PDM from the system tray, if active (click the blueberry icon > exit).
3. In Windows File Explorer, browse to the following location: C:\Users\[USERPROFILE]\AppData\Local\SolidWorks\SolidWorks PDM\Plugins\[vault name]
4. Delete all folders within this location.
5. Don’t log back into PDM just yet. Instead, open the Windows Registry Editor as Administrator.
   1. To do so, search for “regedit” in the Windows Start menu.
6. Navigate to: HKEY_CLASSES_ROOT\CLSID\{Insert your CLSID from step 1 here}
7. Export the key as a backup first by right-clicking the CLSID from the left-hand list > Export. Save this somewhere accessible, like the desktop.
8. Then, right-click > Delete the same key you just exported.
9. Finally, log back into your PDM vault view and then right-click anywhere in an empty spot in the file list to re-register the DLL.

Permissions

Registry

If your Windows user doesn’t have the correct permissions to those same CLSID keys in the registry, you can also see issues. To check this:

1. Open the Registry Editor again. Be sure NOT to run it as admin this time, as we want to determine your user’s permissions specifically.
2. Navigate to the HKEY_CLASSES_ROOT\CLSID\{Insert your CLSID here}
3. Right-click the CLSID key > Permissions.
   
   
   
   
4. In the Permissions dialog, click Advanced.
   
   
   
   
5. Verify your local user account, the Administrator account, and the system all have “full control” permission for that key.
6. If permissions are missing for any of the accounts, you may need to have your IT grant these. You can click Add > select a principal > then add a Windows user. Be sure to grant Full Control access.
7. Once added, reboot the computer and try testing once more.

Folder

The Windows user account may not have permission to write to the C:\Users\[USERPROFILE]\AppData\Local\SolidWorks\SolidWorks Enterprise PDM\Plugins\[vault name] folder. You can check by right-clicking the folder > Properties > the Security tab. Ensure the logged-in user has Full Control permissions.

Conclusion

There are a lot of potential areas of disruption during the add-in distribution process. These are the most common causes for this add-in error, and hopefully, they’ll get you and your users back up and running. If these steps don’t work for you or if you have questions on this issue, however, you can reach out to our Technical Support team for more help if GoEngineer is your VAR.

Want to learn more? Check out more SOLIDWORKS PDM articles below. Additionally, join the GoEngineer Community to participate in discussions, create forum posts, and answer questions from other SOLIDWORKS users. 

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