This version of the Launcher is functionally identical to its predecessor 1.5.4 , but should eliminate the failure due to "can't delete unzip.dll" that some of you encountered when attempting to automatically upgrade from 1.5.2 to 1.5.4. If you have successfully upgraded to 1.5.4 -- either with no difficulties, or by manually cleaning things up after the "can't delete unzip.dll" failure, there is no reason to upgrade to 1.5.5. However, if you did previously encounter the "can't delete unzip.dll" failure and would like to help me verify that 1.5.5 eliminates this problem, I'd appreciate your giving it a try and letting me know. Mirror site operators: please download and post DXLabLauncher155Update.exe on your web site as you normally would, but leave DXLabLauncher154Update.exe on your web site and let your "Available Releases" table continue to reference 1.5.4 -- DXLab Launcher 1.5.4 is still the release that should be used when manually updating the Launcher from a release earlier than 1.5.2. As Rich W3ZJ surmised, the root cause of the "can't delete upzip.dll" failure is the LauncherAgent application's attempt to unzip an archive that contains the file unzip.dll. Unzip.dll contains code for the unzip function, but you can't replace a file containing code that is currently executing -- the "rule" that makes a self-updating Launcher challenging. Depending upon timing, DXLabLauncher 1.5.4 violates that rule. In Launcher 1.5.5, I simply removed unzip.dll from the archive being downloaded, so the LauncherAgent will no longer attempt to replace it. Anyone who has Launcher 1.5.2 (or later) already has an unzip.dll in their Launcher folder anyway. Someone upgrading from a version of the Launcher earlier than 1.5.2 doesn't have unzip.dll installed, however. Such users should perform a manual upgrade to Launcher 1.5.4, which is why I'm asking the mirror site operators to leave DXLabLauncher155.exe on their web sites and keep a 1.5.4 hyperlink in their Available Release tables pointing to it. Future Launcher releases will always involve two files -- one for automatic update by the Launcher, and one for manual update via the an Avaiable Releases table. With an appropriate file naming scheme, we can completely hide this from users -- I'll take this up with the mirror site operators later. Someone installing the Launcher for the very first time will begin with the 1.5.2 full release, which includes the unzip.dll file. The Launcher will then update itself to 1.5.5. 73, Dave, AA6YQ