How to Resolve "Unable to open file" and "The system cannot find the file specified"

Received an error when doing defragmentation on a VM in VMware Workstation.

Unable to open file "C:......Windows XP-cl2-000018.vmdk":
The system cannot find the file specified.

In fact, the specified file Windows XP-cl2-000018.vmdk is still there, it did not disappear. So, what did the error message want to reveal? I looked around and liked to know what was different, and luckily, there was an odd file named:

• Windows XP-cl2-000018-s032.vmdk-dftshkgmw-tmp

The format of file name could be altered by VMware Workstation during defragmentation. So I changed the file name back by removing its trailing extension:

• Windows XP-cl2-000018-s032.vmdk

The VM is back to normal. In fact, the content of the file Windows XP-cl2-000018.vmdk is a file containing a list of child files that can be used to trace the child files are existent or not.

Now we know the source of the problem is not the parent file specified in the error message, we should trace its child files for more clues.