Patent ID: 8090744

Claim:
A computer-implemented method, comprising: determining a set of files of a plurality of files stored on a computer system, wherein for each file in the set, a second version of the file exists in a virtual software layer of the computer system; intercepting an access attempt from an application on the computer system to a first file on the computer system; determining a first compatibility checking mode; determining that a second version of the first file on the computer system exists in the virtual software layer, wherein determining that the second version of the first file on the computer system exists comprises determining that the second version of the first file is a member of the set, and wherein the second version of the first file has a same name as the first file; and in response to said intercepting, said determining the first compatibility mode, and said determining that a second version of the system file exists, attempting to perform the access using the second version of the file.