Error: Command failed: *adb.exe -s emulator-5554 shell “ps ‘uiautomator'””

Especially when working with Appium (1.4.16), Android Studio (2.2.3 and above) and with Android N (7.0) version, execution of test automation script encounters the below error:

Error: Command failed: C:\Windows\system32\cmd.exe /s /c “C:\Users\{user}\AppData\Local\Android\sdk\platform-tools\adb.exe -s emulator-5554 shell “ps ‘uiautomator'””

Error you see in Appium server:

info: [debug] Error: Command failed: C:\Windows\system32\cmd.exe /s /c 
"C:\Users\132266\AppData\Local\Android\sdk\platform-tools\adb.exe -s emulator-5554 shell 
"ps 'uiautomator'""
> 
>     at ChildProcess.exithandler (child_process.js:751:12)
>     at ChildProcess.emit (events.js:110:17)
>     at maybeClose (child_process.js:1016:16)
>     at Process.ChildProcess._handle.onexit (child_process.js:1088:5)
> info: [debug] Responding to client with error: {"status":33,"value":{"message":"A new 
session could not be created. (Original error: Command failed: C:\\Windows\\system32\\cmd.exe 
/s /c \"C:\\Users\\132266\\AppData\\Local\\Android\\sdk\\platform-tools\\adb.exe -s 
emulator-5554 shell \"ps 'uiautomator'\"\"\n)","killed":false,"code":1,"signal":null,"cmd":
"C:\\Windows\\system32\\cmd.exe /s /c \"C:\\Users\\{user}\\AppData\\Local\\Android\\sdk\\
platform-tools\\adb.exe -s emulator-5554 shell \"ps 'uiautomator'\"\"","origValue":
"Command failed: C:\\Windows\\system32\\cmd.exe /s /c \"C:\\Users\\{user}\\AppData\\Local
\\Android\\sdk\\platform-tools\\adb.exe -s emulator-5554 shell \"ps 'uiautomator'\"\"\n"},
"sessionId":null}
> info:

Error in Android studio run console:

org.openqa.selenium.SessionNotCreatedException: A new session could not be created. 
(Original error: Command failed: C:\Windows\system32\cmd.exe /s /c "C:\Users\{user}\AppData\
Local\Android\sdk\platform-tools\adb.exe -s emulator-5554 shell "ps 'uiautomator'""
) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 0 milliseconds

Solution for this error is to append and replace the code in adb.js file present at location

C:\Program Files (x86)\Appium\node_modules\appium\node_modules\appium-adb\lib

Code changes to be done goes as below:

1. Go to adb.js in the path ‘node_modules//appium/node_modules/appium-adb/lib/adb.js’
   ***Find the below**

   ADB.prototype.shell = function (cmd, cb) {
   if (cmd.indexOf('"') === -1) {
   cmd = '"' + cmd + '"';
   }
   var execCmd = 'shell ' + cmd;
   this.exec(execCmd, cb);
   };
   

   Append the below

   ADB.prototype.shell_grep = function (cmd, grep, cb) {
   if (cmd.indexOf('"') === -1) {
   cmd = '"' + cmd + '"';
   }
   var execCmd = 'shell ' + cmd + '| grep ' + grep;
   this.exec(execCmd, cb);
   };
   

2. Find the ‘ADB.prototype.getPIDsByName ‘ and replace the whole section

   ADB.prototype.getPIDsByName = function (name, cb) {
   logger.debug("Getting all processes with '" + name + "'");
   this.shell_grep("ps", name, function (err, stdout) {
   if (err) {
   logger.debug("No matching processes found");
   return cb(null, []);
   }
   var pids = [];
   _.each(procs, function (proc) {
   var match = /[^\t ]+[\t ]+([0-9]+)/.exec(proc);
   if (match) {
   pids.push(parseInt(match[1], 10));
   }
   });
   if (pids.length !== procs.length) {
   var msg = "Could not extract PIDs from ps output. PIDS: " +
   JSON.stringify(pids) + ", Procs: " + JSON.stringify(procs);
   return cb(new Error(msg));
   }
   cb(null, pids);
   });
   };
   

Performing above changes you are good to go ahead, for more detail you can refer to the actual discussion at appium support website