Same here ... forever stuck in update process without success.
I tried downloading the new version, but when running the installer it detects there is an old version and only propose an "update" ... which fail because it doesn't find the file "hamachi-update.msi"
There is a "hamachi-update" file in the folder:
C:\Documents and Settings\NetworkService\Local Settings\Application Data\LogMeIn Hamachi
I tried renaming it to "hamachi-update.msi" but then the installer complains it is not a valid update file.
I noticed that the new downloaded intaller "hamachi.msi" and the "hamachi-update" present in the folder I described above are the same ... same size and if you try to rename the "hamachi-update" to "hamachi-update.msi" and execute it ... you'll have the same installer than the fresh new version ... (shame none of them work though)
Last, I tried uninstalling Hamachi alltogether, and guess what ... it says it can't find the file "hamachi-update" and doesn't let me uninstall... :(