To resolve this issue, follow the steps below:
In HandiTax go to Help, About. Take note of the location of the Hsoft\Apps folder.
All users close HandiTax.
Go to the Hsoft\Apps folder.
Rename the Ht2XX.exe.Config file to HtXX.exe.ConfigOLD. (*XX denotes the relevant year)
If a temp.config file exists, rename it to temp.configOLD.
One user can open HandiTax. This will generate a new Ht2XX.exe.Config file.
The error should now be resolved.
In the event the error occurs due to insufficient disk space, ensure there is enough space in the Local Drive of the computer for the execution of the program.