Hi - I too have experienced the problems - Hamachi Network Icon not showing. Exclamation Mark Yellow Triangle. Digital Signing of Driver disallowing its use so rendering the installation non-working.
My System too is Windows 7 Ultimate SP1
Eventually, took a wide approach of Uninstall & Manual Delete checks
Made Sure Hamachi was STOPPED.
Ran Task Manager to make sure NO 'HAMACHI'
named Processes remained running ... RightClicked and Stopped process and tree.
Ran an UN-Install of Hamachi from the Control Panel-Programs & Features - "Logmein Hamachi" (NOT "Logmein").
Then from Start-Computer(properties)-Device Manager-View(show hidden)
Looked for ALL possible related Network Adapter items, incl. 'TAP'
Hamachi Interface #2 (because whatever I do I cannot locate the #1 to delete...Anywhere !!)
THEN did a File Explorer Search for all references to Hamachi in Windows / System 32 Directory Folders etc. Including
having HIDDEN Files shown in File Explorer. Deleted all instances with Hamachi - most Commonly Hamachi.sys.
THEN Searched for all Registry Entries through Start Run of RegEdit - Searching for any refs
to Hamachi and deleting ALL I would dare to do - avoiding any references that may have had an "overlap"
with other programs etc. And ignoring some which would NOT delete.
Then RE-BOOTED - PC and on re-start Held Down F8 Key - until menu options appeared. At Bootm of Screen near the final Option there is an Option to TURN OFF DRIVER SIGNING CHECKS so that when
next installed it would IGNORE the LACK of DIGITAL SIGNING of the Hamachi Driver Hamachi.sys
Once Re-Booted. Re-Ran Logmein Hamachi MSI installer.
It Completed - No Instance of the MS Windows Digital Signing Error Dialog - SO Install completed,
and didnt 'block' the driver.
Checked the Hamachi Adapter Showed up in the Device Manager -
It DID although it was named "...#2" cos of the buried hidden Adapter/Interface 'somewhere' BUT just have had to ignore that fact. It doesnt seem to matter now.
Checked it was in the Network & Sharing 'Manage Adapters' Dialogs. It was.
Restarted Hamachi - AND all seems OK - Everything SEEMS to now work as expected again.
EXCEPT that running the Diagnostics STILL Quotes the "Inconsistent Timestamp" fault BUT does not
seem to cause and problems (so far) - SO ignoring. BUT Would Like to KNOW WHY it is happening.
Remember to re-boot NORMALLY again so that the Security enforcement of Digital Signing of Drivers that MS Windows requires is Back in Operation.
Thats my experience...Many frustrating Hours of trying to understand whats going on & how to get around it. Hope that it helps someone at least. Good Luck
dp