Simple In/Out Desktop Installation Error "USERNAME is not a valid short file name"
If your users are on a network drive, one solution that has worked for our customers is to set the permissions to the Shared folder (i.e., "users$") to Read (or modified "advanced" read like rights), but each User folder remains only accessible by the specific user. If users cannot all read that one directory, MSI installers may not be able to understand/allocate disk space for the installation.
While there may be other steps you can take to remedy this that involve editing the registry, we recommend using our EXE installer instead. This will install in a way that is immune to the above issue. You can download our EXE installer by heading to Simple In/Out Desktop's website and clicking the Additional Downloads link. From here, click to download the EXE installer.