diff --git a/src/main/scala/net/wiringbits/myphototimeline/CommandAppHelper.scala b/src/main/scala/net/wiringbits/myphototimeline/CommandAppHelper.scala
index 172625f..e48a818 100644
--- a/src/main/scala/net/wiringbits/myphototimeline/CommandAppHelper.scala
+++ b/src/main/scala/net/wiringbits/myphototimeline/CommandAppHelper.scala
@@ -63,11 +63,8 @@ object CommandAppHelper {
     }
 
   def run(source: os.Path, output: os.Path, dryRun: Boolean): Unit = {
-    new FileOrganizerTask().run(
-      inputRoot = source,
-      outputBaseRoot = output,
-      dryRun = dryRun
-    )
+    val args = FileOrganizerTask.Arguments(inputRoot = source, outputBaseRoot = output, dryRun = dryRun)
+    new FileOrganizerTask().run(args)
   }
 
   def findPotentialDate(sourceFile: os.Path): Set[String] = {
diff --git a/src/main/scala/net/wiringbits/myphototimeline/FileOrganizerTask.scala b/src/main/scala/net/wiringbits/myphototimeline/FileOrganizerTask.scala
index 430b904..8ac10b9 100644
--- a/src/main/scala/net/wiringbits/myphototimeline/FileOrganizerTask.scala
+++ b/src/main/scala/net/wiringbits/myphototimeline/FileOrganizerTask.scala
@@ -1,14 +1,29 @@
 package net.wiringbits.myphototimeline
 
+object FileOrganizerTask {
+  case class Arguments(inputRoot: os.Path, outputBaseRoot: os.Path, dryRun: Boolean) {
+    val outputRoot: os.Path = outputBaseRoot / "organized"
+    val duplicatedRoot: os.Path = outputBaseRoot / "duplicated"
+    val invalidRoot: os.Path = outputBaseRoot / "invalid"
+
+    val dataDirectories: List[os.Path] = List(
+      inputRoot,
+      outputRoot,
+      duplicatedRoot,
+      invalidRoot
+    )
+  }
+}
+
 class FileOrganizerTask {
 
-  def run(inputRoot: os.Path, outputBaseRoot: os.Path, dryRun: Boolean): Unit = {
-    val outputRoot = outputBaseRoot / "organized"
-    val duplicatedRoot = outputBaseRoot / "duplicated"
-    val invalidRoot = outputBaseRoot / "invalid"
+  import FileOrganizerTask._
+
+  def run(args: Arguments): Unit = {
+    validate(args)
 
     println("Loading already processed files, it may take some minutes, be patient")
-    val (processedFiles, invalidProcessedFiles) = FileOrganizerService.load(outputRoot)(trackProgress)
+    val (processedFiles, invalidProcessedFiles) = FileOrganizerService.load(args.outputRoot)(trackProgress)
     println(s"Already processed files loaded: ${processedFiles.size}")
     if (invalidProcessedFiles.nonEmpty) {
       println(
@@ -17,7 +32,7 @@ class FileOrganizerTask {
     }
 
     println("Loading files to process, it may take some minutes, be patient")
-    val (filesToProcess, invalidFilesToProcess) = FileOrganizerService.load(inputRoot)(trackProgress)
+    val (filesToProcess, invalidFilesToProcess) = FileOrganizerService.load(args.inputRoot)(trackProgress)
     println(s"Files to process loaded: ${filesToProcess.size}")
     if (invalidFilesToProcess.nonEmpty) {
       println(
@@ -53,39 +68,39 @@ class FileOrganizerTask {
     println(s"- New unique files to organize: ${newUnique.size}")
     println()
 
-    if (dryRun) {
+    if (args.dryRun) {
       println("Files not affected because dry-run is enabled")
     } else {
       // Move duplicated files
-      println(s"Moving duplicated files to: $duplicatedRoot")
+      println(s"Moving duplicated files to: ${args.duplicatedRoot}")
       newDuplicated.zipWithIndex.foreach {
         case (file, index) =>
           trackProgress(current = index, total = newDuplicated.size)
-          FileOrganizerService.safeMove(destinationDirectory = duplicatedRoot, sourceFile = file.source)
+          FileOrganizerService.safeMove(destinationDirectory = args.duplicatedRoot, sourceFile = file.source)
       }
 
       // Move files without metadata
-      println(s"Moving invalid files to: $invalidRoot")
+      println(s"Moving invalid files to: ${args.invalidRoot}")
       invalidFilesToProcess.zipWithIndex.foreach {
         case (file, index) =>
           trackProgress(current = index, total = invalidFilesToProcess.size)
-          FileOrganizerService.safeMove(destinationDirectory = invalidRoot, sourceFile = file)
+          FileOrganizerService.safeMove(destinationDirectory = args.invalidRoot, sourceFile = file)
       }
 
-      println(s"Organizing unique files to: $outputRoot")
+      println(s"Organizing unique files to: ${args.outputRoot}")
       newUnique.zipWithIndex.foreach {
         case (file, index) =>
           trackProgress(current = index, total = newDuplicated.size)
           FileOrganizerService.organizeByDate(
-            destinationDirectory = outputRoot,
+            destinationDirectory = args.outputRoot,
             sourceFile = file.source,
             createdOn = file.createdOn
           )
       }
 
       println("Cleaning up empty directories")
-      FileOrganizerService.cleanEmptyDirectories(inputRoot)
-      FileOrganizerService.cleanEmptyDirectories(outputRoot)
+      FileOrganizerService.cleanEmptyDirectories(args.inputRoot)
+      FileOrganizerService.cleanEmptyDirectories(args.outputRoot)
     }
 
     println("Done")
@@ -103,4 +118,39 @@ class FileOrganizerTask {
       }
     }
   }
+
+  private def exit(msg: String): Unit = {
+    println(s"FATAL: $msg")
+    sys.exit(1)
+  }
+
+  private def validateDirectory(path: os.Path): Unit = {
+    try {
+      lazy val exists = os.exists(path)
+      lazy val isDir = os.isDir(path)
+      if (isDir) {
+        ()
+      } else if (!exists) {
+        os.makeDir.all(path)
+      } else {
+        exit(s"$path is not a directory, or it can't be created")
+      }
+    } catch {
+      case ex: Throwable =>
+        ex.printStackTrace()
+        exit(s"$path is not a directory, or it can't be created")
+    }
+  }
+
+  private def validate(args: Arguments): Unit = {
+    args.dataDirectories.foreach(validateDirectory)
+
+    if (args.outputRoot.toString().startsWith(args.inputRoot.toString())) {
+      exit("The output directory can't be inside the input directory")
+    }
+
+    if (args.inputRoot.toString().startsWith(args.outputRoot.toString())) {
+      exit("The input directory can't be inside the output directory")
+    }
+  }
 }