After following the "keil arm compiler version 5 download" process, verify success:
: Install it into a subfolder within your existing Keil directory to keep tools organized. For example: C:\Keil_v5\ARM\ARM_Compiler_5.06u7 Avoid Special Characters
Select the latest maintenance release (usually ). 2. MDK Legacy Support Pack
Some old ARMCC 5 executables use packing technology similar to malware. This is a false positive. Whitelist the Keil_v5 folder.
Here’s the current status and how to get it if you need it for legacy projects.