diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79bf5e812..8051c58d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
     * Grav 1.7: Fixed error on page initialization [#2753](https://github.com/getgrav/grav/issues/2753)
     * Fixed checking ACL for another user (who is not currently logged in) in a Flex Object or Directory
     * Fixed bug in Windows where `Filesystem::dirname()` returns backslashes
+    * Fixed Flex object issues in Windows [#2773](https://github.com/getgrav/grav/issues/2773)
 
 # v1.7.0-rc.2
 ## 12/04/2019
diff --git a/system/src/Grav/Common/Flex/Pages/PageObject.php b/system/src/Grav/Common/Flex/Pages/PageObject.php
index a513bc8fe..45b347674 100644
--- a/system/src/Grav/Common/Flex/Pages/PageObject.php
+++ b/system/src/Grav/Common/Flex/Pages/PageObject.php
@@ -19,6 +19,7 @@ use Grav\Common\Flex\Pages\Traits\PageRoutableTrait;
 use Grav\Common\Flex\Pages\Traits\PageTranslateTrait;
 use Grav\Common\Page\Pages;
 use Grav\Common\Utils;
+use Grav\Framework\Filesystem\Filesystem;
 use Grav\Framework\Flex\FlexObject;
 use Grav\Framework\Flex\Pages\FlexPageObject;
 use Grav\Framework\Route\Route;
@@ -108,7 +109,8 @@ class PageObject extends FlexPageObject
                 // TODO: this should not be template!
                 return $this->getProperty('template');
             case 'route':
-                $key = dirname($this->hasKey() ? '/' . $this->getKey() : '/');
+                $filesystem = Filesystem::getInstance(false);
+                $key = $filesystem->dirname($this->hasKey() ? '/' . $this->getKey() : '/');
                 return $key !== '/' ? $key : null;
             case 'full_route':
                 return $this->hasKey() ? '/' . $this->getKey() : '';
@@ -151,8 +153,10 @@ class PageObject extends FlexPageObject
      */
     protected function reorderSiblings(array $ordering)
     {
+        $filesystem = Filesystem::getInstance(false);
+
         $storageKey = $this->getStorageKey();
-        $oldParentKey = ltrim(dirname("/$storageKey"), '/');
+        $oldParentKey = ltrim($filesystem->dirname("/$storageKey"), '/');
         $newParentKey = $this->getProperty('parent_key');
 
         $slug = basename($this->getKey());
diff --git a/system/src/Grav/Common/Flex/Pages/PageStorage.php b/system/src/Grav/Common/Flex/Pages/PageStorage.php
index 3d244f4ec..0c3b59437 100644
--- a/system/src/Grav/Common/Flex/Pages/PageStorage.php
+++ b/system/src/Grav/Common/Flex/Pages/PageStorage.php
@@ -14,6 +14,7 @@ namespace Grav\Common\Flex\Pages;
 use Grav\Common\Debugger;
 use Grav\Common\Grav;
 use Grav\Common\Language\Language;
+use Grav\Framework\Filesystem\Filesystem;
 use Grav\Framework\Flex\Storage\FolderStorage;
 use RocketTheme\Toolbox\File\MarkdownFile;
 use RocketTheme\Toolbox\ResourceLocator\UniformResourceLocator;
@@ -260,7 +261,10 @@ class PageStorage extends FolderStorage
         } else {
             [$order, $folder] = ['', $objectKey];
         }
-        $parentKey = ltrim(dirname('/' . $key), '/');
+
+        $filesystem = Filesystem::getInstance(false);
+
+        $parentKey = ltrim($filesystem->dirname('/' . $key), '/');
 
         return [
             'key' => $key,
@@ -610,8 +614,10 @@ class PageStorage extends FolderStorage
         // Update parent timestamps.
         foreach (array_reverse($list) as $storage_key => $meta) {
             if ($storage_key !== '') {
+                $filesystem = Filesystem::getInstance(false);
+
                 $storage_key = (string)$storage_key;
-                $parentKey = dirname($storage_key);
+                $parentKey = $filesystem->dirname($storage_key);
                 if ($parentKey === '.') {
                     $parentKey = '';
                 }
diff --git a/system/src/Grav/Common/Flex/Pages/Traits/PageRoutableTrait.php b/system/src/Grav/Common/Flex/Pages/Traits/PageRoutableTrait.php
index dc3612684..8b9b64f41 100644
--- a/system/src/Grav/Common/Flex/Pages/Traits/PageRoutableTrait.php
+++ b/system/src/Grav/Common/Flex/Pages/Traits/PageRoutableTrait.php
@@ -16,6 +16,7 @@ use Grav\Common\Page\Interfaces\PageCollectionInterface;
 use Grav\Common\Page\Interfaces\PageInterface;
 use Grav\Common\Page\Pages;
 use Grav\Common\Utils;
+use Grav\Framework\Filesystem\Filesystem;
 
 /**
  * Implements PageRoutableInterface.
@@ -46,9 +47,11 @@ trait PageRoutableTrait
         /** @var Pages $pages */
         $pages = Grav::instance()['pages'];
 
+        $filesystem = Filesystem::getInstance(false);
+
         // FIXME: this does not work, needs to use $pages->get() with cached parent id!
         $key = $this->getKey();
-        $parent_route = dirname('/' . $key);
+        $parent_route = $filesystem->dirname('/' . $key);
 
         return $parent_route !== '/' ? $pages->find($parent_route) : $pages->root();
     }
diff --git a/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php b/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
index b4b48133c..c42273d75 100644
--- a/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
+++ b/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
@@ -20,6 +20,7 @@ use Grav\Common\Yaml;
 use Grav\Framework\Cache\CacheInterface;
 use Grav\Framework\File\Formatter\MarkdownFormatter;
 use Grav\Framework\File\Formatter\YamlFormatter;
+use Grav\Framework\Filesystem\Filesystem;
 use Grav\Framework\Flex\FlexDirectory;
 use Grav\Framework\Flex\Interfaces\FlexCollectionInterface;
 use Grav\Framework\Flex\Interfaces\FlexIndexInterface;
@@ -285,7 +286,9 @@ trait PageLegacyTrait
      */
     public function copy(PageInterface $parent = null)
     {
-        $parentStorageKey = ltrim(dirname("/{$this->getMasterKey()}"), '/');
+        $filesystem = Filesystem::getInstance(false);
+
+        $parentStorageKey = ltrim($filesystem->dirname("/{$this->getMasterKey()}"), '/');
 
         /** @var FlexPageIndex $index */
         $index = $this->getFlexDirectory()->getIndex();
diff --git a/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php b/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
index f5167e9e6..ecc718395 100644
--- a/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
+++ b/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
@@ -15,7 +15,7 @@ use Grav\Common\Page\Interfaces\PageCollectionInterface;
 use Grav\Common\Page\Interfaces\PageInterface;
 use Grav\Common\Page\Pages;
 use Grav\Common\Uri;
-use Grav\Framework\Flex\Interfaces\FlexObjectInterface;
+use Grav\Framework\Filesystem\Filesystem;
 use RocketTheme\Toolbox\ResourceLocator\UniformResourceLocator;
 
 /**
@@ -389,8 +389,9 @@ trait PageRoutableTrait
             $var,
             function ($value) {
                 if (null === $value) {
+                    $filesystem = Filesystem::getInstance(false);
                     $value = $this->getMasterKey() ?: $this->getKey();
-                    $value = ltrim(dirname("/{$value}"), '/') ?: '';
+                    $value = ltrim($filesystem->dirname("/{$value}"), '/') ?: '';
                 }
 
                 return $value;
@@ -415,8 +416,9 @@ trait PageRoutableTrait
             return null;
         }
 
+        $filesystem = Filesystem::getInstance(false);
         $directory = $this->getFlexDirectory();
-        $parentKey = ltrim(dirname("/{$this->getKey()}"), '/');
+        $parentKey = ltrim($filesystem->dirname("/{$this->getKey()}"), '/');
         if ($parentKey) {
             $parent = $directory->getObject($parentKey);
             $language = $this->getLanguage();
diff --git a/system/src/Grav/Framework/Flex/Storage/FolderStorage.php b/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
index d9a3f9eba..b20990eba 100644
--- a/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
+++ b/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
@@ -14,6 +14,7 @@ namespace Grav\Framework\Flex\Storage;
 use Grav\Common\Filesystem\Folder;
 use Grav\Common\Grav;
 use Grav\Common\Utils;
+use Grav\Framework\Filesystem\Filesystem;
 use Grav\Framework\Flex\Interfaces\FlexStorageInterface;
 use RocketTheme\Toolbox\File\File;
 use InvalidArgumentException;
@@ -620,8 +621,9 @@ class FolderStorage extends AbstractFilesystemStorage
             if (isset($options['file'])) {
                 $pattern .= '/{FILE}{EXT}';
             } else {
+                $filesystem = Filesystem::getInstance(true);
                 $this->dataFile = \basename($pattern, $extension);
-                $pattern = \dirname($pattern) . '/{FILE}{EXT}';
+                $pattern = $filesystem->dirname($pattern) . '/{FILE}{EXT}';
             }
         }
         $this->prefixed = (bool)($options['prefixed'] ?? strpos($pattern, '/{KEY:2}/'));
diff --git a/system/src/Grav/Framework/Flex/Storage/SimpleStorage.php b/system/src/Grav/Framework/Flex/Storage/SimpleStorage.php
index 20a129daf..4019f2fef 100644
--- a/system/src/Grav/Framework/Flex/Storage/SimpleStorage.php
+++ b/system/src/Grav/Framework/Flex/Storage/SimpleStorage.php
@@ -12,6 +12,7 @@ declare(strict_types=1);
 namespace Grav\Framework\Flex\Storage;
 
 use Grav\Common\Filesystem\Folder;
+use Grav\Framework\Filesystem\Filesystem;
 use InvalidArgumentException;
 
 /**
@@ -42,11 +43,13 @@ class SimpleStorage extends AbstractFilesystemStorage
         $formatter = $options['formatter'] ?? $this->detectDataFormatter($options['folder']);
         $this->initDataFormatter($formatter);
 
+        $filesystem = Filesystem::getInstance(true);
+
         $extension = $this->dataFormatter->getDefaultFileExtension();
         $pattern = basename($options['folder']);
 
         $this->dataPattern = basename($pattern, $extension) . $extension;
-        $this->dataFolder = \dirname($options['folder']);
+        $this->dataFolder = $filesystem->dirname($options['folder']);
         $this->keyField = $options['key'] ?? 'storage_key';
 
         // Make sure that the data folder exists.
diff --git a/system/src/Grav/Framework/Flex/Traits/FlexMediaTrait.php b/system/src/Grav/Framework/Flex/Traits/FlexMediaTrait.php
index 6304e786c..310ee6910 100644
--- a/system/src/Grav/Framework/Flex/Traits/FlexMediaTrait.php
+++ b/system/src/Grav/Framework/Flex/Traits/FlexMediaTrait.php
@@ -18,6 +18,7 @@ use Grav\Common\Page\Medium\Medium;
 use Grav\Common\Page\Medium\MediumFactory;
 use Grav\Common\Utils;
 use Grav\Framework\Cache\CacheInterface;
+use Grav\Framework\Filesystem\Filesystem;
 use Grav\Framework\Flex\FlexDirectory;
 use Grav\Framework\Form\FormFlashFile;
 use Psr\Http\Message\UploadedFileInterface;
@@ -177,9 +178,11 @@ trait FlexMediaTrait
         }
 
         try {
+            $filesystem = Filesystem::getInstance(false);
+
             // Upload it
             $filepath = sprintf('%s/%s', $path, $filename);
-            Folder::create(\dirname($filepath));
+            Folder::create($filesystem->dirname($filepath));
             if ($uploadedFile instanceof FormFlashFile) {
                 $metadata = $uploadedFile->getMetaData();
                 if ($metadata) {
@@ -211,8 +214,10 @@ trait FlexMediaTrait
         $grav = Grav::instance();
         $language = $grav['language'];
 
+        $filesystem = Filesystem::getInstance(false);
+
         $basename = basename($filename);
-        $dirname = dirname($filename);
+        $dirname = $filesystem->dirname($filename);
         $dirname = $dirname === '.' ? '' : '/' . $dirname;
 
         if (!Utils::checkFilename($basename)) {
@@ -237,7 +242,7 @@ trait FlexMediaTrait
             $locator->clearCache($targetFile);
         }
 
-        $fileParts  = pathinfo($basename);
+        $fileParts  = $filesystem->pathinfo($basename);
 
         if (!file_exists($targetPath)) {
             return;