Fatal Error when activating Hummingbird

When trying to activate Hummingbird I get a Fatal Error of too many bytes trying to be allocated in object-cache.php. Could possibly be related to W3 Total Cache. This was removed from the site a while ago, but seems that some files were left over. I thought I removed them all but not sure if I got them. Any assistance would be greatly appreciated.

*Update - I increased allowed memory to 256M in wp-config.php in case it was related to that. Hummingbird will activate now, but then the site becomes accessible in incognito mode giving the same Fatal Error. To get it working I have to manually deactivate Hummingbird by changing the plugin folder name.