2011 Aug 23 The HMC procedure code has changed significantly. If you already have a copy of the HMC.ipf procedure file installed in the appropriate directory, it should update as normal. If you experience problems, however, remove HMC.ipf and follow the installation instructions below. Note, however, that the new version requires Igor Pro 6.2 or later.
The HMC menu uses another procedure file, AutoUpdate.ipf to monitor for new versions of Igor procedures and to update them automatically for you. The basic installation procedure for the HMC menu now is first to install AutoUpdate.ipf and then use a one-line command to install the HMC.ipf file.
You should now have the HMC menu near the right of the Igor menu bar.
Once you have installed AutoUpdate.ipf and HMC.ipf, each time you launch Igor (which loads both file), Igor will check with this server to see if an updated version of either is available. If it is, it will ask if you'd like to update. Unfortunately, if you don't have a network connection, Igor will issue an error. I have tried to trap for this, but cannot intercept the error before the warning is posted. Just ignore it.
Detailed information about the HMC menu