Error: "SEP Installation failed with error code 1603"
Symantec Endpoint Protection (SEP) Installation failing with buffer overflow on Windows 7 and Windows 10
Error status 1603 or error code 1603 in Install logs
The SYSTEM account does not have enough permissions on the destination folder for the Windows Installer package. The Windows Installer service uses the SYSTEM account to install software.
The System doesn't have the latest version of the MSI installer.
The System TEMP and TMP variables are not set to the default path C:\windows\temp.
In most cases, Windows defender should be turned off automatically during SEP installation. However, in some rare cases Windows Defender remain on and block the SEP installation.
System issue/Possible OS corruption
Check and provide necessary permission to the account
Ensure the machine has the latest version of MSI Installer
Set the System TEMP and TMP variables path to C:\windows\temp
Windows Defender need be turned off by manual. But the turn off option is grey in Windows Service List.
In Windows 10 Enterprise Edition, Windows Defender can be turned off by GPO.
In Windows 10 Home Edition, there is no GPO, the only way to resolve it is editing registry.
win+r, input "regedt32" to open registry；
find the hive “HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender”
right-click on the right window and select “New” > “DWORD (32bit) value”
name the “DWORD (32 bit) value as “DisableAntiSpyware" ，and set the value as 1
confirm and restart computer