If you are using Photoshop via Adobe Creative Cloud on Windows 7, the Creative Cloud desktop app itself might hold a damaged database.
To fix a "damaged installer" error for Adobe Photoshop on Windows 7, the most effective solution is to to verify the file's integrity . Top Solutions for "Damaged Installer" on Windows 7 Install the Digital Certificate : Locate your Photoshop Set-up.exe file. Right-click the file and select Properties . adobe damaged installer fix photoshop windows 7 top