I am running Windows 7 64-bit and Eclipse also 64-bit with the latest ADT plugin installed and the Android ADK. All installed as instructed on the Android SDK site.
Go to the following directory in your computer:
C:\Users\.android\avd
Inside this directory you will find all files and directories with the definition and content of your avd machines-
Now do the basic troubleshooting steps:
-check if the avd directory exists and if it contains a file with the name "sdcard.img".
-if the file exists, try to rename it (to check if its locked) and then go to eclipse and ask to create a new sd card.
-if it fails, try to create manualy a file with that name to check premissions.
good luck
I found similar issue on my windows. Seems like this happen for 64 bit machines only. To solve this, make sure you have full access permission to all files under the Tools folder in Android SDK directory. For linux/ubuntu, execute the following
chmod -R 777 ../tools
For windows, goto Android SDK directory..
Right click Tools folder > Properties > Go to tab "Security" > Select "Users" > Edit > Select "full control", save and close it.
It should work after doing this
Close the emulator which is in open, and re-try. This worked for me.