PHD 2.5 instance already running error

If you are getting this error “PHD2 instance 1 is already running” on a Mac OS X El Capitan, you need a version of PHD2.5 that is compiled with the latest OS Version.  Luckily I have it for download.

The new version of PHD 2.5 that you can download on the main site (at the time of this blog) gives some problem to users using Mac OSX version 10.11 (El Capitan) because the available downloadable package was compiled with lower version of OSX.

I have managed to compile it and it’s available for download. PHD 2.5 Compiled in Mac OSX El Capitan.

For more information about PHD2


There’s  a problem with Orion StarShoot Autoguider as I have already reported that it wasn’t able to find the camera and fails to continue and hung up.  Here’s a link to a previous version that I’m not sure where to find it and that’s the reason I’m sharing it here. PHD2.5 good for Orion StarShoot Autoguider

For the detail of the bug, it can be found here PHD2.5 Orion StarShoot bug


2 thoughts on “PHD 2.5 instance already running error”

  1. Hello there, ran the latest dev version, then yours. Crashes when I try to connect to the Orion Starshoot. It works with the simulator (only have one camera). However I have both instances of PHD2 on my computer. Should I blow away the old version? Would you like log files and which ones?

    FWIW, the old PHD2.5 works once every ten times.

    1. I have the same issue with the Orion StarShoot Autoguider. Right now the quick fix is whenever you opened/launched PHD2.5, select the different camera first, I haven’t tried Simulator but on my case, I have the ZWO camera. Once it got that correctly, then you can switch to your Orion StarShoot Autoguider and that works for me 99% of the time.

      The error we’re getting is because of the Orion StarShoot Autoguider not fully compatible with El Capitan. Once they got something new then that might fix the problem.


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