Who is this article for?
CrashPlan for Small Business, yes.
Code42 for Enterprise, yes.
Link: Product plans and features.
This article applies to version 4.
If your backup is able to get to a high 90+% but never seems to get to 100%, check in the History tab and look for the message Unable to back up (number of) files. This troubleshooting article can direct you to a solution.
Under the hood
The message Unable to back up files (next attempt within X minutes) means that CrashPlan is trying to back up certain files but can't access them, either because the file is open and in use by another application (and the normal method of backing up open files is failing), or because the file is locked due to permissions or other issues. CrashPlan will continue trying to back up the file. Typically, once the file is closed, it will be backed up.