This has become a major headache for our classroom installations where students have their 'My Documents' folder on a network server. After the installation of ArcHydro the startup of the Toolbox goes up from 10 seconds to about 90 seconds on an empty document and even more if a data is loaded in Arcgis. I tried the latest 2.1.0.98 and also in Arcgis 10.1 the 10.1.0.9 . If the 'My Documents' is on the local system it is not such a big problem but this cannot be changed in our environment. Can the default folder be changed in Arcgis ?
By the way would it be possible to change the MSI guid when the version of ArcHydro changes. This would make deployment of the MSI files easier.