The process cannot access the file because it is being used by another process.
Works well on my machine, this is not a VS2015 problem. A common environmental issue, this error message is a standard tragedy on Windows computers that are infected with shrink malware.
Signing is a two-step process. The first link.exe file should generate the executable needed for the SHA256 hash to be computed for the file. Then the file is opened again by ALINK (managed by the linker) to add the signature. It must fight other processes that run on your machine that are also interested in the file. This type, which invariably gets its underwear in the kit when the executable file appears, it would seem, is nowhere, and insists on checking the contents of the file and excluding access to the file before it is completed.
Everything seems to work fine when you use a subscription delay, the delay is usually enough to force the process to complete its work and release the exclusive file lock. In addition, there are some chances that sn.exe is a little more complicated in this, try again to open the file periodically before giving up, ALINK, of course not.
You must make an exception in your antivirus product for your directory. If this is some kind of aggressive freeware such as Avast, AVG or ESET, then plan to get rid of it as soon as possible so that it can no longer bother you. The protector never bothers me.