Microsoft .NET 4.7 installation problem or “blocked” by installer

Some computers installed with Microsoft Windows 7 may not install the .NET Framework 4.7 update correctly. Computers which are not updated to the .NET Framework 4.7 may be prompted to install the Framework when starting TODDS or Caseworx after an update, but do not complete successfully with an error message.

Users of Windows 10 and 8.1 should experience no issues with the .NET 4.7 update. However, Windows 7 and 8 users may get a message from the Microsoft update package for .NET 4.7 stating that their update was blocked. The required file that needs to be installed is available from Microsoft at the following URL:

Once this patch has been installed, users can then successfully install the .NET 4.7 Framework. Users can also directly install the .NET 4.7 Framework from the following URL:

If the Framework appears to install correctly, but still persists with erratic program behavior, reboot the computer and try the program again.

Dentrix Error After Update/Install

It has been noted that some versions of Dentrix is incompatible with Microsoft’s .NET 4.6 and Windows 10. Users who update their Windows Vista, 7, 8, or 8.1 to .NET 4.6 may find that some or all parts of Dentrix may not function correctly after the update.

Caseworx and TODDS install .NET 4.6 by default if not found, but can also run under .NET version 4.5.2. If problems are noted after the .NET Framework update, contact Dentrix Support for update procedures required to patch their older software to the current version. This is NOT an error with your Windows install, computer’s hardware, and/or JKL Software’s products.

Dentrix information for .NET 4.6 and Windows 10 can be found here:

As of the publish date of this support article, the Dentrix patch can be found on their website at . The patch can be downloaded from the link by clicking on the “Attachments” link on the page.

“Unknown Hard Error” during Microsoft .NET 4.5.1 – 4.6 update (or install)

Some installations of Caseworx and TODDS have exhibited an error showing “Unknown Hard Error” and not completing the Microsoft .NET Update for versions 4.5.1, 4.5.2, and 4.6. This may occur during the installation of the product,  or after an update. The error does not occur in the program itself, but rather the Microsoft installer that is updating the .NET technology.


The most common cause seems to be that the Microsoft RyuJIT preview was installed on the machine at one time. This preview version prevents the final version in .NET 4.6 from completing the install


The preview version must be removed and all traces of it’s registry/environment must be reset.


The following involves editing the registry and environmental variables. If you are unsure or uncomfortable performing these steps, contact your IT professional.

  1. Open the Registry Editor and look for the following key:
    If found, remove the key from the registry. Also, check the left side of the registry editor or any subkeys labeled “AltJit”. If found, remove the subkey also.
    Download the following registry file and double-click it to clear the setting (you can safely ignore any browser/antivirus warnings, it only removes the above listed entry):
  1. Go to Control Panel, System, “Advanced System settings” (left side). On the panel that appears, click the “Environment Variables” button at the bottom. Look at the bottom of the window that appears in the section titled “System Variables” and look for an item named “COMPLUS_AltJit”. If found, highlight and delete it.
  1. Then, go to Control Panel, Programs and Features, and look for “Microsoft .net RyuJIT Preview”. Uninstall it if found. Also, look for Microsoft .NET Framework 4.6. Uninstall it if found.
  2. Install the Microsoft .NET 4.6 Framework from You may be asked to reboot your computer. Perform the reboot if asked.
  3. Start TODDS/Caseworx, it may or may not ask for the .net 4.6 update. If it does require additional .net items, proceed with the .net update. It should succeed with these items cleared.
  4. If you continue to get the “Unknown Hard Error” message, and did not reboot in step 4, perform a reboot – a Windows program that was running probably prevented all files from updating successfully.