Finding a "free download" for Cubase 5 is a common but tricky search. Because it’s old (released in 2009) and high-value, it has a "long story" involving compatibility issues and licensing changes.
We strongly advise against this route.
Key Features of Cubase 5
Cubase 5 was released by Steinberg in 2009 and is now considered unsupported legacy software. While you may find mentions of "free downloads," please be aware that Cubase 5 was never released as freeware; it requires a valid license to operate legally. Technical Overview for 64-Bit Systems cubase 5 setup exe free download 64 bit
Installing Cubase 5 Setup EXE