Apps Error launching app in virtual device (Eclipse)

[Fernando]

Hello!

I'm a beginner in the design of applications for Android.
I'm using Android SDK and Eclipse with the ADT Plugin 22.6.2, trying to test my first (Hello World) application on a virtual device (I don't have a real one).
When I launch the app I get the following error message:

[2014-04-14 11:08:08 - MyFirstApp] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'AVD_Nexus'
[2014-04-14 11:08:08 - MyFirstApp] Uploading MyFirstApp.apk onto device 'emulator-5554'
[2014-04-14 11:08:12 - MyFirstApp] Installing MyFirstApp.apk...
[2014-04-14 11:08:36 - MyFirstApp] Installation error: Unknown failure
[2014-04-14 11:08:36 - MyFirstApp] Please check logcat output for more details.
[2014-04-14 11:08:36 - MyFirstApp] Launch canceled!


Can someone help me?
Need more information? Just tell me.
Suggestions?


Thank you in advance and apologies for my English.
Fernando

 

[ProjectLiquid]

Can you start the virtual device first, then run your app?

 

[Fernando]

Yes!
I created a virtual device with the Virtual Device Manager, marked as a valid Android virtual device. Then, the device started normally, but the app didn't.

 

[ProjectLiquid]

What errors are you getting in logcat?

 

[Fernando]

Suddenly the app began to work!
I don't know why.
Now I'm going to keep learning.
Thank you for your help!