# builing on OSX XCode 12.0
**URL:** https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286
**Category:** Support
**Created:** [September 23, 2020, 10:10am UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286 "2020-09-23T10:10:44Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@djduke](https://discourse.vtk.org/u/djduke)
#### Post date: [September 23, 2020, 10:10am UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/1 "2020-09-23T10:10:44Z")
I’ve recently bumped my OSX to 10.15.6 (Catalina) with XCode 12.0 and have run into issues rebuilding VTK from a fresh git checkout. I have Python3 installed via MacPorts
The build goes fine. However when I try to run VTK:
vtkpython
dyld: Library not loaded: @rpath/Python3.framework/Versions/3.8/Python3
Referenced from: /usr/local/bin/vtkpython
Reason: image not found
Abort trap: 6
I haven’t changed shell so my paths should be the same. Looking at my environment and CMake settings I can’t see anything that looks wrong. Any suggestions on how to correct would be welcome.
thanks
David
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### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [September 23, 2020, 2:40pm UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/2 "2020-09-23T14:40:19Z")
Hmm. I’d make sure that your Python3 cache variables are consistent (all from MacPorts or all from the SDK). It appears as though you might have the MacPorts executable with the SDK framework?
If everything is the SDK library, you’ll need to add a flag `CMAKE_INSTALL_RPATH` to contain…wherever that `Python3.framework` exists.
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### Author:  [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)
#### Post date: [September 23, 2020, 8:24pm UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/3 "2020-09-23T20:24:34Z")
I have run into the same problem. When running from the VTK build directory, you’ll want to add `CMAKE_BUILD_RPATH:STRING=/Library/Developer/CommandLineTools/Library/Frameworks/` to your CMakeCache.txt file, run cmake again, and build again. Then it should work.
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### Author:  [@djduke](https://discourse.vtk.org/u/djduke)
#### Post date: [September 24, 2020, 6:42pm UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/4 "2020-09-24T18:42:35Z")
Thanks Cory.
In the process of implementing your suggestions I found that my xcode update had not been successful. once I’ve been able to repair it I’ll be able to try recompiling.
regards
David
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### Author:  [@djduke](https://discourse.vtk.org/u/djduke)
#### Post date: [October 18, 2020, 4:33pm UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/5 "2020-10-18T16:33:19Z")
still stuck on this. I’ve set RPATH in my CMakeLists file, its currently:
/Library/Developer/CommandLineTools/Library/Frameworks/
if I look in that directory I see
Python3.framework/
Yet running vtkpython gives
dyld: Library not loaded: @rpath/Python3.framework/Versions/3.8/Python3
However the Python3.framework directory does include Version/3.8 etc
Am I misinterpreting RPATH and including/missing a component?
Toconfirm the CMakeLists line is:
set(CMAKE\_BUILD\_RPATH:STRING="/Library/Developer/CommandLineTools/Library/Frameworks/")
I reconfigured rebuilt, re-installed, all from a fresh git clone
thanks
David
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### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [October 19, 2020, 12:56pm UTC](https://discourse.vtk.org/t/builing-on-osx-xcode-12-0/4286/6 "2020-10-19T12:56:20Z")
> [@djduke](#):
>
> set(CMAKE\_BUILD\_RPATH:STRING=“/Library/Developer/CommandLineTools/Library/Frameworks/”)
You’re confusing CMake syntax and the command line syntax. Either one will work:
- `cmake -DCMAKE_BUILD_RPATH:STRING=…` (command line)
- `set(CMAKE_BUILD_RPATH "…")` (CMake code)