# fatal error C1905: Front end and back end not compatible (must target same processor).

### Question

• Hello,

I am facing issue to build an COM dll for 64-bit environment.

I have followed the steps given at http://msdn.microsoft.com/en-us/library/9yb4317s%28v=VS.80%29.aspx

Still getting above error. I am using VS2005.

If any one knows answer and replies to this that will be great help!

Monday, August 30, 2010 10:39 AM

### All replies

• There are two very different 64-bit architectures - the Itanium ('IA64') and the more usual AMD64 ('X64') architecture.  The instruction sets cannot be mixed.

I'm going to guess that you intend building for 'X64', but that you have specified 'IA64' in error because that is the first type suggested on the page you cite.

To fix this, go to your Linker Properties/Target Machine and specify 'MachineX64 (/MACHINE:X64)'.

Also, you can look up errors such as the C1905 using the help function in Visual Studio.  This would take you to a page such as Fatal Error C1905 which gives more information on the error.

Monday, August 30, 2010 11:42 AM

But I have checked the Linker Properties/Target Machine and that is 'MachineX64 (/MACHINE:X64) ' and I am building for X64 only.

Error is same.

Where will I get the front end and back end compiler information on my system?

Tuesday, August 31, 2010 8:05 AM
•

Hi,

I suppose that some components miss when you install Visual Studio 2005, so you do better add these components when you find out install file and reinstall it.

Have a nice day!

Jesse

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Wednesday, September 01, 2010 9:21 AM
•

Hi,

Did you solve your problem? If so please share the solution with us!

Have a good day!

Jesse

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
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Friday, September 03, 2010 1:56 AM
• I was having the same issue and I don't think this is the answer at all.

The cause of my problem was a static library which had been built for x86. I had recompiled it for x64 but forgot to add x64 to my library path so the linker was still trying to link to the x86 version.

I would suggest checking that all static libraries have been compiled for x64 and if so, that your linker input path has been updated to pick up the correct lib build.

Example:

old - c:\path\to\lib project\$(ConfigurationName) new - c:\path\to\lib project\x64\$(ConfigurationName)

Hope this helps.

Regards,

Larry Dikshit

Monday, January 24, 2011 12:28 PM