Webroot scare in safemode

I have webroot secure anywhere with over 10months subscription.
I wanted to format an external hard drive, which had come from a computer with a problem, suspected motherboard failure, had not considered possibility of virus.
With the external hard drive there were problems with formatting, it, the quick format window was unresponsive and I had to hard shut down my computer, which took a few minutes instead of being quick (I have an ssd for main OS). When it restarted with the check computer screen routine I chose safe mode. When Win 7 pro safe mode opened, I tried to turn on webroot because I wanted to scan my computer right away in safemode. Webroot appeared to be expired, out of date, would not scan, and worse than that, that all my computer security was turned off. Very concerned at this point that a virus from the external hard drive had set in. System settings gave no access to system restore. I rebooted my computer and allowed it to open windows normally. Webroot subscription fine and scanned quickly without problem. Still concerned, why would webroot not be able to work while in safe mode, very unsettling, at that time thinking I had a serious virus which webroot had failed to protect me from, and it would be a major process of reinstalling windows and the rest of my system,  to be free of it?