Just now installed splunk.6.6 on Windows10 and loggedin. Uninstalled it.
installed again with new location for SPLUNKHOME to c:\splunk\
Installation is successful, created a new user, changed password search query index=internal sourcetype=splunkd says no results.
tried with index=* , again no results.
time window changed to 24 hours by default, instead of All time.
this is an usual one. the _internal index gets data later.
trying adding some sample data / log files, the tutorial data (http://www.splunk.com/base/images/Tutorial/Sampledata.zip) .. then internal index will get data.
As its my local installation, I moved the local folder from C:\Splunk\etc\apps\SplunkForwarder\ away, restarted splunk. Started working.
Mus anwered earlier
forward enabled. Disabled it. Restarted splunk.