Run your downloaded Warcraft_III_1.31_Patch.exe as Administrator. The high-quality installer will automatically detect your installation path (e.g., C:\Program Files (x86)\Warcraft III ).
Note: As of 2020, Blizzard Entertainment officially migrated all players to Reforged (Patch 1.32+). Patch 1.31 is a "Classic" legacy patch. To play it, you generally need to own the original CD keys or use specific archival tools. Warcraft 3 Frozen Throne Patch 1.31 Download High Quality
: The addition of 64-bit support allowed the game to utilize larger memory pools, drastically reducing crashes on complex custom maps. Run your downloaded Warcraft_III_1
If you currently have Reforged installed, you cannot simply "downgrade" without a full reinstall. Uninstall Reforged completely via Windows Settings. Warcraft 3 Frozen Throne Patch 1.31 Download High Quality