Thank you for your post. Please could you try the following:
1) Ensure all Microsoft Updates have been installed.
2) Any antivirus installed (other than Microsoft Defender) may need to be stopped or removed (if free).
3) Use the right click on the installer file and use “Run as Administrator” for the install.
If the above still doesn’t work, and you are still encountering this database cluster issue, you need to ensure that you delete the Exactal folder from C:\ProgramData\Exactal (the programdata directory is hidden by default).
Once deleted, empty the recycle bin, then proceed with the new installation.
If you don’t delete the Exactal folder, the old database will still be there.
Hope this finally resolves your issue!
iTWO costX Forum Admin