LabVIEW VIs have four basic security levels; unlocked, locked with no password, locked with password, and block diagram removed. In the cases where a VI is locked, a user (not knowing the password or how to unlock the VI), can only see the front panel and can not get at the block diagram. However, the locked VI still has the block diagram code, which can be automatically recompiled to newer versions of LabVIEW. A VI that has had its block diagram removed, no longer has its source code, all that is left is the front panel image and the compiled set of instructions that specify how the VI executes. Since the source code is no longer present, LabVIEW can not convert the VI from one version to another. There are a number of ways in which block diagrams may be removed from a VI, the most common being to save an Application Distribution from the File>>Save As menu.
In most cases, if you do not have a backup copy of a VI which still has the block diagram, you would be out of luck. However, Close File+.vi is a file that ships with LabVIEW, and should be located in the ..\LabVIEW 7.1\vi.lib\Utility\file.llb library. You should change any references in your VIs that call Close File+.vi to point at the version of the VI in file.llb. Please note that it is possible that the Close File+.vi in your llb has the same name as the NI version but is a different VI. If that is the case, then you will not be able to upgrade the VI that you have.
Thank you for your explanation. I have both LabVIEW version 6.0.2 & 7.1. However, when i try to open the Close File+.vi using labVIEW version 6.0.2. I noticed that I m unable to view its block diagrams. So are there any other way, which i can retrieve the block diagram of the Close File+.vi? Thanks for your help!
I've taken the 6.1 version of close file+ and saved it for the previous version. You may have to relink the file to the error code VI. Note: this is not the entire file.llb! Do not replace your own file.llb with this one.