ERDAS Software 2009 and higher: To install a new version of ERDAS software, to include LPS 9.3 and higher, you need not uninstall the old version first. Each version installs in a separate directory. You may uninstall the old version first, but it is not a requirement.

ERDAS version 9.2 and earlier: To install a new version of ERDAS IMAGINE, you need not uninstall the old version first. Each version installs in a separate directory. You may uninstall the old version first, but it is not a requirement. To install a new version of LPS, you must uninstall the older LPS version first, to avoid conflicts with different versions of the same COM objects.

When uninstalling ERDAS software before or after upgrading to the next version, fixes must be uninstalled first. Fixes must be uninstalled in the reverse order of installation (last in, first out). The best way to uninstall fixes is to use the Install Manager at Start > All Programs > ERDAS 2011 > Install Manager, since it allows you to review what has been installed, and uninstalls in the correct order. While it is also possible to uninstall fixes using Windows' Add or Remove Programs, it is not as convenient, since the fix uninstallers will still require you to follow the last-in, first-out order, and the Windows utility does not keep track of that. Once all fixes have been removed, continue to remove the ERDAS software.