diff --git a/app/code/Magento/Config/Model/Placeholder/Environment.php b/app/code/Magento/Config/Model/Placeholder/Environment.php
index 961a29e7b249354172cf4a91d8e2b57850369a80..b5c1c6be89c2f23a031102590514c026730827b0 100644
--- a/app/code/Magento/Config/Model/Placeholder/Environment.php
+++ b/app/code/Magento/Config/Model/Placeholder/Environment.php
@@ -71,6 +71,6 @@ class Environment implements PlaceholderInterface
      */
     public function isApplicable($placeholder)
     {
-        return 1 === preg_match('/(' . static::PREFIX . '.*[a-zA-Z_]).*/', $placeholder);
+        return 1 === preg_match('/^' . static::PREFIX . '([a-zA-Z]+)([a-zA-Z0-9_])*$/', $placeholder);
     }
 }
diff --git a/app/code/Magento/Config/Test/Unit/Model/Placeholder/EnvironmentTest.php b/app/code/Magento/Config/Test/Unit/Model/Placeholder/EnvironmentTest.php
index a4557503921d952be1eec8dbc9a5891346f98d91..6d1113a7750c54ab5246352b3aa5eb66799011d9 100644
--- a/app/code/Magento/Config/Test/Unit/Model/Placeholder/EnvironmentTest.php
+++ b/app/code/Magento/Config/Test/Unit/Model/Placeholder/EnvironmentTest.php
@@ -84,8 +84,8 @@ class EnvironmentTest extends \PHPUnit_Framework_TestCase
     public function testIsApplicable($placeholder, $expected)
     {
         $this->assertSame(
-            $this->model->isApplicable($placeholder),
-            $expected
+            $expected,
+            $this->model->isApplicable($placeholder)
         );
     }
 
@@ -98,6 +98,9 @@ class EnvironmentTest extends \PHPUnit_Framework_TestCase
             [Environment::PREFIX . 'TEST', true],
             ['TEST', false],
             [Environment::PREFIX . 'TEST_test', true],
+            [Environment::PREFIX . '-:A', false],
+            [Environment::PREFIX . '_A', false],
+            [Environment::PREFIX . 'A@#$', false]
         ];
     }
 }
diff --git a/lib/internal/Magento/Framework/Crontab/CrontabManager.php b/lib/internal/Magento/Framework/Crontab/CrontabManager.php
index a60bd9d2cb512ac0000941657e76db1f0be20b85..2b597b8eb638fb21af887ab7b47490f5533fafae 100644
--- a/lib/internal/Magento/Framework/Crontab/CrontabManager.php
+++ b/lib/internal/Magento/Framework/Crontab/CrontabManager.php
@@ -192,7 +192,7 @@ class CrontabManager implements CrontabManagerInterface
     {
         if (stripos(PHP_OS, 'WIN') === 0) {
             throw new LocalizedException(
-                new Phrase('Your operation system is not supported, you cannot work with crontab')
+                new Phrase('Your operation system is not supported to work with this command')
             );
         }
     }