This is the error I receive: "The address wasn’t understood Firefox doesn’t know how to open this address, because one of the following protocols (ms-excel) isn’t associated with any program or is not allowed in this context. You might need to install other software to open this address." Reinstalling Office 365 Business x86 didn't resolve the issue. Replacing Office 365 Business x86 with Office 365 Business x64 didn't resolve the issue. Reinstalling, refreshing and running Firefox with no addons didn't resolve the the issue.