Run GenPatcher.exe as administrator, point it to your Command & Conquer: Generals or Zero Hour folder, and follow the on-screen prompts.
Thanks to everyone who reported issues with the previous version! genpatcher v2.12
GenPatcher v2.12 has been released! This update brings important fixes and compatibility improvements for older Generals / Zero Hour installations. Run GenPatcher
Check the included Readme.txt or ask in the support channel. Run GenPatcher.exe as administrator