I just downloaded Eclipse Galileo and installed ADT10 and tried to a phonegap app using this guide: http://www.phonegap.com/start But each time i try to build im getting this error: Unknown error: Unable to build: the file dx.jar was not loaded from the SDK folder!
I know that there are already some questions/answers about it in this forum but they didnt work for me.
Updating Android SDK platform-tools with the Android SDK Manager and restarting Eclipse did it for me
It happened to me, either, and it happens because I've changed to win7, and install the latest ADT to eclipse, but I used my old Android SDK. Finally, I fix this problem by updating my Android SDK to the latest version.
Even after reinstalling "Android SDK platform-tools" in my UBuntu-16.04 LTS problem persisted. I am using Eclipse-Oxygen. Copying dx.jar from /build-tools/25.0.3/lib into /build-tools/26.0.0-preview/lib solved my problem.
For me, eclipse was looking in the wrong place for the SDK Manager. To fix this I did
NOTE: The SDK manager tells you what dir it is using near the top of the UI.
I had installed a new version of eclipse that has the ADT bundled up from the Android developer site, but when I opened eclipse it was looking at the old SDK.exe location.
hth