Hello
I am very new here but today I downloaded Arduino-0017 and "installed" it while keeping Arduino-0016. 0017 does not compiled with an error of paths or other similar. So I "RARed" all my 0016 and erased it from my drive to see what happened with "preferences.txt". I saw some changes but I do not understood it very well. So I deleted it and arranged the windows so I can see the 0017 AND the "preferences.txt" folder. 0017 wrote a new "preferences.txt" and compiled OK. It seems to work. I am not expert so I can not say for sure anything, but I think that if that file changed a lot, in the Arduino.cc web page there must be a note about deletions, changes, renaming, etc. of files. I AM NOT COMPLAINING AT ALL, only saying someone forgot something. Arduino is a very good program.
AVE arduino programatori salutami. 
Hector
Sorry but i dont get your problem.
If you want to delete your installed release just move it into pastebin.
You dont need to rar something to delete it.
@traffiq
Thank you for your answer. Not a problem, only telling what happened to me.
I RARed my 0016 folder to keep it, just in case, sometimes I change an example to try something and just wanted to keep that.
The idea was that I was able to get to work 0017 after erasing the preferences.txt and 0017 creates a new one.
Maybe only maybe this can help others.
Unless your short of disk space, I've always found it useful to have several versions installed, presently versions 11, 12 and 17. They seem to not interfere with each other as far as I can tell.
Lefty
0017 does not compiled with an error of paths or other similar.
From this quote and mention of preferences.txt, I believe the OP is referring to this 0017 bug report. This is the third report I have seen for this problem. I consider it a major failure is regression testing of the IDE that should be rectified for the next release. I am surprised no-one found it in the pre-release testing of 0017.
Unless your short of disk space, I've always found it useful to have several versions installed, presently versions 11, 12 and 17. They seem to not interfere with each other as far as I can tell.
As reported by myself and Eberhard in bug report 79, 0016 and 0017 do not coexist.
As reported by myself and Eberhard in bug report 79, 0016 and 0017 do not coexist.
Hi Mike, that statement is not correct. I installed 0017 and my 0016 continues to function correctly. I am running Windows XP SP3.
There may be some cases where they don't play well but why do you think that a significant number of people are unable to use both?
I think eberhard's report related to the case where 0017 was run with a version 0016 that did not have a preferences file. As mellis posted in this issue report, this is not a likely scenario.
You should be able to run both Arduino 0016 and 0017 on the same computer. If you have problems launching one, try deleting your preferences file, running Arduino 0016, quitting, and then running 0017.