Recently I upgraaded *downgraded? to the current Arduino release (I think it was the 1.0.5) and ran into a problem. The attiny boards I had uploaded under the board dropdown are gone and Ive spent the last day trying to add them again. Now heres where my situation differs from other peoples. I then went back to Arduino 1.0.4 which had the boards and they were gone also. So I have no idea how to fix this. What should I do? Ive followed the directions, tutorials, etc to no avail. I knew I shouldn't have upgraded. 
My computer skills are just above basic so maybe thats whats wrong.
Make sure you re-start the Arduino IDE when you install anything. It only looks for boards.txt files and library files on start up.
That's a basic problem if the Attiny core files were installed under the IDE folders. A better place is to install them under the sketches\hardware folder. That way when you update the IDE you don't loose any customizations.
Which Attiny core were you using?
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Make sure you unzip the files to where the default sketches folder is. It should be something like \My Documents\Arduino\hardware\attiny. Then rename the file "Prospective Boards.txt" to just boards.txt. And restart the IDE.
Ive been using the MIT core but just downloaded the one from google code. I extracted it to \Documents\Arduino\hardware\attiny\ so its under the attiny folder which I had to create. the files in attiny are bootloaders, cores, boards.txt, license, and README. I started the arduino software and nothing shows up under boards. Anybody know what Im doing wrong?
Are you sure you are on the IDE 1.0.x and not the 1.5.2?
Check the IDE File->Preferences, where does the Sketchbook location: point to? The hardware folder should be under that path.
It says its Arduino 1.0.5 I opened preferences and it says \Documents\Arduino. Hardware is under that and Ive enclosed a screen shot of what that looks like.
@Swri9217
I have used the ATtinys since version 1.0 and have upgraded the toolset twice with my current version at 1.0.5 and all of my ATtiny definitions as well as my custom board descriptions (I have multiple "boards.txt" files) have been preserved.
The only advice I have is to bring up 1.0.5 and to double-check the preferences option to ensure that your Arduino home directory path is set correctly. A misque here will keep the application from finding the boards.txt files during application start-up.
OR, you can make a copy of the 1.0.5 master boards.txt file under Program Files\Arduino... and simply ADD your specific content there. Of course, this is not recommended practice, but it will work as long as you do not overwrite with an update. While in the file (After making a copy) you may wish to remove definitions for official Arduino boards that you do not currently have as this simplifies the selection pick menu in the GUI.
Ray
Swri9217:
It says its Arduino 1.0.5 I opened preferences and it says \Documents\Arduino. Hardware is under that and Ive enclosed a screen shot of what that looks like.
The preferences do not look correct. It should have the full path shown not just \Documents\Arduino.
It should be something more like, C:\Documents and Settings\User\My Documents\Arduino.
From the Preferences menu you can just click on the Browse button and make sure you select the correct folder.
Woops! I thought I copied it right oh well. C:\Users\Wrigley5\Documents\Arduino thats what it realy says.
Swri9217:
Woops! I thought I copied it right oh well. C:\Users\Wrigley5\Documents\Arduino thats what it realy says.
If this is where you want your default sketches folder to be then you need to move the attiny folder under this path. According to your screenshot you have the attiny under a different path,
\My Documents\Arduino\hardware\attiny.
It will need to be under here.
C:\Users\Wrigley5\Documents\Arduino\hardware\attiny
Success! Thanks guys for your help! A friend showed me in person how to do it and it finaly clicked with me.
Swri9217:
Success! Thanks guys for your help! A friend showed me in person how to do it and it finaly clicked with me.
What was the fix?
He cleared the hardware folder and made a folder in it called tiny and extracted everything in to it. Im pretty sure thats what I did about 10 times before. I uploaded the blink sketch to Attiny85 chip and it works.
I am having the same problem.. been to preferences and chose the Arduino folder ...the tree is "/Users/leozacharias/Documents/Arduino"
inside Arduino I have... hardware/attny containing (boards.txt, bootloaders folder, cores folder, license.txt, README)
I reload the Arduino IDE and nothing is added in the boards list!
Baffling!
Should not matter but you are probably the first person to use the folder name "attny" instead of "tiny".
...inside Arduino I have... containing (boards.txt ...
You followed the instructions and copied entries from Prospective Boards.txt to boards.txt?
You can try Google Code Archive - Long-term storage for Google Code Project Hosting.
...
This file has been deprecated. Another file would probably be better. Do you want to continue?
Links to the latest versions are always in the center panel towards the top...
https://code.google.com/p/arduino-tiny/