A virtual machine(VM) can be simply created upon use and disposed upon the completion of the tasks or the detection of error. The disadvantage of this approach is that if there is no malicious activity, the user has to re-do all of the work in her actual workspace since there is no easy way to commit (i.e., merge) only the benign updates within the VM back to the host environment. In this work, we develop a VM commitment system called Secom to automatically eliminate malicious state changes when merging the contents of an OS-level VM to the host. Secom consists of three steps: grouping state changes into clusters, distinguishing between benign and malicious clusters, and committing benign clusters. Secom has three novel features. First, it leverages OS-level information flow and malware behavior information to recognize malicious changes. Second, it identifies malicious objects on a cluster by cluster basis. Third, it simultaneously considers two malware behaviors that are of different types and the origin of the processes that exhibit these behaviors, rather than considers a single behavior alone as done by existing malware detection methods. Experiments show that our prototype can effectively eliminate malicious state changes while committing a VM with small performance degradation.