Acquia Dev Desktop and Drush broken with syntax is incorrect I did a clean install of Acquia Dev Desktop (Build Nov 13th, 2017) under Windows 10. I can clone my site (Drupal 8) and then click to open my local Drush console. It opens a DOS prompt into the docroot directory. When I execute any drush commands I get "The filename, directory name, or volume label syntax is incorrect." 

Here is a sample:


  C:\DevDesktop\website-dev\docroot>drush -d -d  version  
  
  Loading drushrc "C:\Program Files (x86)\DevDesktop\tools\vendor\drush\drush\drushrc.php" into "drush" scope.   [bootstrap]  
  
  [0.78 sec, 2.48 MB]
  Cache HIT cid: 8.1.15-commandfiles-0-61c5476a3a04a40d4bdadfd521f0641f [0.84 sec, 2.52 MB]                          [debug]
  
  Begin redispatch via drush_invoke_process(). [1.16 sec, 6.43 MB]                                                  [notice]
  
  Backend invoke: "C:\DevDesktop\website-dev\docroot\vendor\bin\drush.launcher"                            [command]
  --root="C:\DevDesktop\website-dev\docroot" --debug --verbose  version 2>&amp;1 [1.21 sec, 6.45 MB]
  
  Calling proc_open("C:\DevDesktop\website-dev\docroot\vendor\bin\drush.launcher"  --root="C:\DevDesktop\website-dev\docroot" --debug --verbose  version 2>&amp;1);
  
  The filename, directory name, or volume label syntax is incorrect.
  End redispatch via drush_invoke_process(). [1.24 sec, 6.44 MB]                                                    [notice]
I was also facing the same issue on windows 10 with Acquia Dev Desktop and configured existing Drupal 8 project from a client.
Following three things what I did worked for me.
I simply:

Removed directory vendor/drush
Removed directory vendor/bin
Removed line &quot;drush/drush&quot;: &quot;^8.1&quot; from composer.json which is located on docroot directory.

Now, default drush is working for me as you can see the default drush version at C:\Program Files (x86)\DevDesktop\tools\composer.json.
Hopefully, this will help someone else.