If you are installing an upgrade version of Data Explorer, you should not install the new version over your current version. You should either remove the previous version of Data Explorer, or install the new version in a different directory. If you would like to install a new version of Data Explorer, but want the prior version to remain the default, then you can use the -noconfig option to the installdx script. This will install the new version, but will not set up the links which cause it to be the default installation. Note that you can use the DXROOT environment variable to specify which version of Data Explorer you want to use if you have multiple versions. DXROOT should point to the top level installation directory.