AutoCAD freezes or stalls when you turn Ortho mode on, possibly by pressing the F8 key.
This issue seems to be resulting from a Windows 10 update.
AutoCAD or F/X CAD 2017 and Newer
Autodesk has created a Hotfix file to address this issue for versions 2017 and newer.
1. Download the Hotfix file from the Autodesk website. (In most cases, the appropriate file for your installation will be the third one in the list – 64-bit for AutoCAD 2017.)
2. Close CAD.
3. Double-click the downloaded file to unzip it.
4. Double-click the unzipped file.
5. Open CAD.
You should now be able to use Ortho mode without issue.
Is Ortho mode still freezing CAD? Try setting the TEMPOVERRIDES system variable to 0.
AutoCAD or F/X CAD 2016 and Older (TEMPOVERRIDES Solution)
Type TEMPOVERRIDES in the Command line, and press Enter.
When prompted to Enter new value for TEMPOVERRIDES, type 0 and press Enter. You should now be able to use Ortho mode without freezing AutoCAD.