FAQ‎ > ‎Troubleshooting‎ > ‎


Welcome to the gray button page, the page where all your troubles will be solved. Or at least you will get lots of info on how to troubleshoot the gray button.


The gray button refers to the button on the Blocks Editor that you click to connect to a device. If it can not see a device, a phone or the emulator, it is not active, it's gray.

"Summoned, I take the place that has been prepared for me. I am Grey. I stand between the candle and the star. We are Grey. We stand between the darkness and the light." 
  Delenn - Babylon 5

Many of the gray button issues on Windows are driver issues. On Linux it can be you skipped setting up a rules file and it mostly works on a Mac.

The way to debug the gray button is

  1. make sure Java is set up
  2. make sure you have installed the latest App Inventor Setup
  3. make sure the emulator works
  4. make sure 'adb device' returns your device
  5. make sure you are in the right mode
and then post what you did, what you are getting and the Java console log to the Getting Set Up and Connecting Your Phone to App Inventor group.

Here is the post I put into that group with some details. It also gets you there

and always "Listen to the music and not the song." Kosh - Babylon 5

verifying java is enabled

After installing the latest version of java runtime, you need to make sure that it's enabled. Also, if you have multiple versions installed you might not have the correct one enabled.

Go to the Windows Control Panel, Open the Java Control Panel, Click the Java tab at the top, and click View. Once there, make sure enabled is checked for the latest version.
A visual guide is available on the App Inventor Info Center - http://www.taiic.com/troubleshooting/enable-java


If what you want to do is to use App Inventor and you can get the web page to come up and the Blocks Editor to load, then it will be music in your ears to hear that you do not need to solve the gray button issue. You can use the barcode/ QR code and install your app without the emulator or a connected device.

Click 'Show Barcode' and the Blocks Editor will compile your app and display a barcode. Scan the barcode and you will download the app to your phone where you can install and run it.

This example of a QR code will not take you anyplace useful (unless you are me). It is to an app I wrote to look at what an empty app looks like. 

The source attached at the bottom of this page (togb.zip) was built and tested using the barcode. Try it, it is a great option if your button is gray.

Here's a video that shows using the QR code to install an app.

One of the FAQs points out that the barcode is useful if you are working with lots of media files

You need a barcode reader to read barcodes. I use the ZXing Barcode Scanner from the market.

list of modes for various phones

You should normally use Charge Only. IF you try to use it with the phone mounted as a drive, you will get an error. 

To get the mode:
  1. Connect your USB cable
  2. pull down the notification panel from the top of the screen
  3. tap USB Connection
  4. tap the mode for your device to make that the default connection type
I have got confirmation for the following devices:
  • HTC Evo 4g
  • Motorola Droid X
  • Motorola Droid 2
Let us know if you have a different mode that works.

ViewSonic ViewPad 7 on Mac OS X

Info on the forums at

where to get (mostly Windows) drivers for various phones


Download and install the Motorola MotoConnect software from
should work for all devices

Recently the link has not worked. Someone got it to work by setting up a developer account and then the link worked

You can have problems if you install the drivers manually. Here is one person's description of how he handled the situation with his Droid X


conversation on the App Inventor group:

good post that includes where to find the drivers on the phone


ZTE Racer 


comment on getting adb to work with them
galaxy apollo
galaxy apollo

Archos 43

Archos released drives at their FTP page at ftp://support.archos.com

No reports of using these drivers... yet (anyone?)

Drivers linked at the thread at http://forum.archosfans.com/viewtopic.php?f=63&p=280632

these worked for someone

read the App Inventor forum for more info

Archos 5 with Ubuntu

device code


from Samsung's site

Samsung USB Driver for Windows
The USB Driver for Windows is available for download in this page. 

You need the driver only if you are developing on Windows and want to connect a Samsung android device to your development environment over USB.

Worked on a Galaxy Tab and Galaxy Europa. Probably works for all Samsung devices.

and another message in the forum

and someone that got a galaxy apollo working

Nexus S

 a few comments

Huawei U8150

The driver is in the phone

Optimus V


About half way down the page it says "Download" They worked on my Optimus V
V=Virgin Mobil  S= Sprint

list from android developers

devices that have connected

We set up a form to collect data on connecting phones to the Blocks Editor. The form is (currently) here

And results, are a link for now.

Thanks to all that updated the form. 
If you are not connecting with your phone review the steps to make sure...
and if you are still having problems, post in the Getting set up... forum

debugging app

These are the slides that are loaded into the debugging app.

The gray button is what we see if the Blocks Editor can not find a device to connect with. 

a good connection

the landing page on V0_8

no connection from V0_8

How to package. Did I say I developed and debugged togb using the barcode?

These are the buttons you see in the Blocks Editor or info panels that come up from there.

This is the gray button


your choice... If all else fails, continue without a device and use the barcode

once a device or emulator is found

looking for something to talk with

what you want to see

already emulating - no problem

I said to use a phone but forgot to plug one in

Emulator Specific

External Storage Error

If you are receiving the following error, it means the SD card is not mounted in the emulator.
See the quick guide on tAIIC for steps to resolve this issue.Click HERE

Emulator not connecting

Try deleting Java cache.
Get pointers to forum to help understand...

Gary Frederick,
Dec 17, 2010, 9:10 AM
Gary Frederick,
Dec 17, 2010, 9:10 AM