Error installing LR4 - digital signature is not trusted

Report · Aug 17, 2020

Trying to install my old 4.0 version of Lightroom on my macBook Air and receive the error: "Adobe Photoshop Lightroom 4.pkg can’t be installed because its digital signature is not trusted."

I have searched other posts and tried a few suggestions but have not been successfull.

Any ideas?

Report · Aug 17, 2020

Which version of MacOS is running on your MacBook?

My System: Intel i7-8700K - 64GB RAM - NVidia Geforce RTX 3060 - Windows 10 Pro 22H2 -- LR-Classic 13.2 - Photoshop 25.6 - Nik Collection 6.9 - PureRAW 4 - Topaz Photo AI 2

Report · Aug 17, 2020

macOS Catalina 10.15.6

Report · Aug 17, 2020

Lightroom 4 cannot be installed on Catalina.

Report · Aug 17, 2020

While LR v4 may be a 64bit app, the installer is not. The installer is 32bit.

You can not run a 32bit app in Catalina.

Report · Aug 17, 2020

Boot into an older OS that CAN support a 32-bit installer (like Mojave), install, then you should be able to run LR, at least I can run LR5, under Catalina. LR4? Maybe, maybe not.

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

Adobe Community

Error installing LR4 - digital signature is not trusted

1 Correct answer