I am getting an error on a 64 bit Win 7 machine 'application failed to start because its side by side configuration is incorrect' can anyone tell me what causes this and how to fix it/?
That's a system error, indicating a problem with the side-by-side DLL configuration for the application.
Side-by-side, or SxS, is a ... controversial ... feature Microsoft added to Windows in an attempt to relieve the so-called "DLL Hell" problem, or at least break DLL handling in new and exciting ways.
Windows now has a directory named %windir%\winsxs which contains a huge number of subdirectories (18000 on this machine), each with a particular version of some DLL. Applications have "manifests" which tell Windows just what versions of various DLLs they want, and Windows will look for those versions of those DLLs under winsxs. This lets the system have multiple versions of a DLL "side by side", hence the name.
The manifest can be linked into the application program (or DLL, when one DLL depends on another), or it can be a separate file. If your application is named foo.exe, for example, it may have a file named foo.exe.manifest. When the manifest is a separate file, it has to be in the same directory as the executable file it applies to.
There are myriad online articles about the "side by side configuration is incorrect" error message. See for example this one, from Microsoft, for Access 2010: support.microsoft.com/.../2525435.
As that article implies, there may be more information in the Windows Application Event Log. Start the Windows Event Viewer, open the Application log, try to run your program again, and refresh the log view - there may be a new message with additional information.
Unfortunately there are various reasons why this problem can occur. Sometimes installing a newer version of the Microsoft C runtime ("Visual C redistributable package"), which can be downloaded from Microsoft, will fix it.
Thank you I will investigate further, but now on another application which has been running with no problems for a while, we now get the error 'Component comctl32.ocx or one of its dependencies is not correctly registered a file is missing or invalid' . Have never some across this before, any ideas what might cause it? The application works on 32 bit machines but causes this error on a 64 bit machine
We have run into this and solved the issue by installing the appropriate Visual C Redistributable Package.
I will point out a couple of specifics to add to Michael's excellent description because the vcredist package you use is dependent on the runtime.
1) You state that you are getting the error on a 64-bit machine. If you are using the 32-bit runtime, you have to install the 32-bit vcredist (vcredist_x86.exe) to address the issue. The 64-bit vcredist (vcredist_x64.exe) won't help even though you running on a 64-bit system.
2) The version of vcredist you need is dependent on the version of the runtime you are using. If I remember correctly, the version 8.x runtimes required the 2005 vcredist. The current runtime (9.2.2) requires the 2010 vcredist (for Visual C 10.0).
For the 32-bit 9.2.2 runtime, you can download vcredist_x86 2010 SP1 at:
For the 64-bit 9.2.2 runtime, you can download vcredist_x64 2010 SP1 at: