This is not an error; it's a feature. If you download v5 specifically for old code, you are on the right track. Issue 4: Windows Defender or Anti-Virus Quarantines armcc.exe Cause: Arm Compiler 5 uses code obfuscation for licensing, which some aggressive AVs flag as suspicious.
A: Yes, but install them into different folders (e.g., C:\Keil_v5_536 and C:\Keil_v5 ). Use the respective project launchers. keil arm compiler version 5 download
Last updated: October 2025. Information based on Arm Keil MDK release notes and community testing. Always refer to official Arm documentation for licensing changes. This is not an error; it's a feature