Like many people, I’ve had problems installing org-mode using elpa, resulting in the well known error
Invalid function: org-with-silent-modifications
This is usually due to not following the installation instructions:
When installing from ELPA, please do so from a fresh Emacs session where no org function has been called.
I’ve encountered this problem a few times on Windows installations, each time through forgetting the above advice. The solution was straightforward, go to (home)/emacs.d/elpa and delete the org file, temporarily rename the .emacs file so that you’re restarting Emacs to a completely fresh session (or start a fresh emacs without any customization with emacs -q -thanks to iNecas). After that org-mode installs without a hitch.
And then I tried to do the same on Linux. Same error, same attempted solution.
This time it didn’t work. I wasted half on hour on this until I tried a complete reboot of the PC. This time it worked. The lesson is, when it says fresh Emacs session, it means a completely fresh Emacs session.
Tony Ballantyne Tech 
Thanks for the post. It helped a lot. Just a small note: you can start a fresh emacs without any customization with
emacs -qLikeLike
Thanks for the tip! I’ll update the post.
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Thanks for the tip! Removing the compiled files (*.elc) in the org directory also works.
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Cheers! And thanks for your tip…
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Thanks! this tip was most useful, it solved a problem that was driving me nuts for two days.
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You’re welcome!
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I installed org 8.3.5 in elpa and I met with a problem when I was using it.
When I enter C-c C-e to export for a html-file, after enter “h h”, it doesn’t output a html-file in my working path, instead, it comes out an information:”Definition not found for footnote 0″.
Can you tell me why?And how to slove it?
Thank you very much!
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Sounds like you need to clean up your source file. Try exporting it in chunks to see what works and doesn’t.
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Export in chunks?How?
I’ve install it once again, and doesn’t work either.
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Try exporting a small file with not much in it. If this exports normally, it suggests that the problem is in the big file you’re exporting. Try breaking the big file up into sections and exporting each part, see where the problem lies.
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