Spectrum Installation is taking a very long time (2 plus hours). Any idea what may cause this? 

Checking the Installation logs and there is a rolling message: 

3 [main] perl 11892 child_info_fork::abort: F:\win32app\Spectrum\NT-Tools\SRE\bin\cygperl5_26.dll: Loaded to different address: parent(0xE80000) != child(0xE10000)

Release : 10.3

Component : SPECTRUM CORE

Searching online on "cygperl5_26.dll: Loaded to different address" and several forums on the error can be found. 

The most common reason is having Anti-Virus running at the time of install. 

Recommend to verify Anti-Virus is DISABLED and re-do the installation. 

Issue may also be conflict in Cygwin library files within the OS. try /usr/bin/rebaseall -v or cd /usr/bin && ./rebaseall -v

Here are some links for reference: 

https://stackoverflow.com/questions/37602608/cygwin-error-child-info-forkabort-loaded-to-different-address

https://stackoverflow.com/questions/9300722/cygwin-error-bash-fork-retry-resource-temporarily-unavailable

https://support.microsoft.com/en-us/help/4561616/windows-10-update-kb4561616