How to Fix Your Windows Computer if It Won’t Communicate with Your TI-84

How to Install Programs on a TI-84 Plus Calculator From Windows

Recently, some models of Windows PC’s (Windows 11) have begun blocking Texas Instruments 84 calculators from successfully connecting to the computer to transfer files.

When you connect a calculator to the computer, your computer will either not register the calculator, or an error message will pop up that says something to the effect of “Driver has been blocked: tihdusb.sys does not pass the Windows driver policy.”

There are many fixes proposed on various how-to pages on the internet, but they don’t work.

So, if your TI-84 calculator is not connecting to Windows, try this.

This is the actual fix (it’s actually easy when you do it):

1. Uninstall TI-Connect software using the Control Panel’s “Add/Remove Programs…”
2. Hold Shift and Click Restart
3. Upon restart, go to Troubleshoot –> Advanced –> Start-Up Settings and restart again
4. Upon restart, select Disable Driver Enforcement (should be 7)
5. Upon restart, reinstall TI-Connect. The fix should hold until you restart your computer again.

Hopefully, Texas Instruments will update its drivers so that its calculators can again connect to a PC.

P.S. Thanks to David Blobaum for help with debugging this issue!