Did you uninstall the previous version, before installing the current one?
No, I thought it would update the old version. After uninstalling both, I installed version 5 before my 1st post.
Have you tried installing in Safe Mode and/or installing as administrator?
Thanks for the suggestions. These didn't work though.
Could it be registry entries? With no version installed I find e.g.:
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Regedit\LastKey=Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Seagate\SeaTools
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UFH\SHC\0=C:\ProgramData\Microsoft\Windows\Start Menu\Programs\SeaTools\SeaTools.lnk
C:\Program Files (x86)\Seagate\SeaTools5\SeaTools.exe
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UFH\SHC\2=C:\ProgramData\Microsoft\Windows\Start Menu\Programs\SeaTools\SeaTools.lnk
C:\Program Files (x86)\Seagate\SeaTools5\SeaTools.exe
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UFH\SHC\4=C:\ProgramData\Microsoft\Windows\Start Menu\Programs\SeaTools\SeaTools.lnk
C:\Program Files (x86)\SeaTools5\SeaTools.exe
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UFH\SHC\6=C:\ProgramData\Microsoft\Windows\Start Menu\Programs\SeaTools\SeaTools.lnk
C:\Program Files (x86)\SeaTools5\SeaTools.exe
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Compatibility Assistant\Store\C:\Program Files (x86)\SeaTools5\SeaTools.exe
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\FTH\State\C:\Program Files (x86)\SeaTools5\SeaTools.exe
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\FTH\State\C:\Program Files (x86)\Seagate\SeaTools\SeaTools.exe
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\C:\Program Files (x86)\Seagate\SeaTools5\SeaTools.exe