If you're looking to learn radio planning:
If you or your organization owns an Atoll license (any version up to 3.4), you can log into the official Infovista support portal. Under "Downloads" > "Legacy Versions", you will find the exact Atoll 3.4 download 64-bit installer (usually named Atoll_3.4.0_Setup_x64.exe). Atoll 3.4 Download 64 Bit
Cause: You accidentally downloaded the 32-bit version or have an incompatible Windows (e.g., Windows 10 in S Mode).
Fix: Verify the filename includes x64. Disable S Mode via Settings > Activation. If you're looking to learn radio planning: If