diff --git a/lib/Service/Install/InstallService.php b/lib/Service/Install/InstallService.php
index 6caf46bac1..8e69ff7b0f 100644
--- a/lib/Service/Install/InstallService.php
+++ b/lib/Service/Install/InstallService.php
@@ -23,6 +23,7 @@
 use OCA\Libresign\Handler\JSignPdfHandler;
 use OCP\AppFramework\Services\IAppConfig;
 use OCP\Files\AppData\IAppDataFactory;
+use OCP\Files\Folder;
 use OCP\Files\IAppData;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotFoundException;
@@ -87,7 +88,7 @@ public function setArchitecture(string $architecture): void {
 		$this->architecture = $architecture;
 	}
 
-	private function getFolder(string $path = '', ?ISimpleFolder $folder = null): ISimpleFolder {
+	private function getFolder(string $path = '', ?ISimpleFolder $folder = null, $needToBeEmpty = false): ISimpleFolder {
 		if (!$folder) {
 			$folder = $this->appData->getFolder('/');
 			if (!$path) {
@@ -103,6 +104,10 @@ private function getFolder(string $path = '', ?ISimpleFolder $folder = null): IS
 		}
 		try {
 			$folder = $folder->getFolder($path, $folder);
+			if ($needToBeEmpty) {
+				$folder->delete();
+				throw new \Exception('Need to be empty');
+			}
 		} catch (\Throwable $th) {
 			try {
 				$folder = $folder->newFolder($path);
@@ -118,6 +123,10 @@ private function getFolder(string $path = '', ?ISimpleFolder $folder = null): IS
 		return $folder;
 	}
 
+	private function getEmptyFolder(string $path): ISimpleFolder {
+		return $this->getFolder($path, null, true);
+	}
+
 	/**
 	 * @todo check a best solution to don't use reflection
 	 */
@@ -346,8 +355,8 @@ public function installJava(?bool $async = false): void {
 			$this->runAsync();
 			return;
 		}
+		$folder = $this->getEmptyFolder($this->resource);
 		$extractDir = $this->getFullPath() . '/' . $this->resource;
-		$javaFolder = $this->getFolder($this->resource);
 
 		/**
 		 * Steps to update:
@@ -373,9 +382,9 @@ public function installJava(?bool $async = false): void {
 		$checksumUrl = $url . '.sha256.txt';
 		$hash = $this->getHash($compressedFileName, $checksumUrl);
 		try {
-			$compressedFile = $javaFolder->getFile($compressedFileName);
+			$compressedFile = $folder->getFile($compressedFileName);
 		} catch (NotFoundException $th) {
-			$compressedFile = $javaFolder->newFile($compressedFileName);
+			$compressedFile = $folder->newFile($compressedFileName);
 		}
 		$comporessedInternalFileName = $this->getDataDir() . '/' . $this->getInternalPathOfFile($compressedFile);
 
@@ -427,13 +436,14 @@ public function installJSignPdf(?bool $async = false): void {
 			$this->runAsync();
 			return;
 		}
+		$folder = $this->getEmptyFolder($this->resource);
 		$extractDir = $this->getFullPath() . '/' . $this->resource;
 
 		$compressedFileName = 'jsignpdf-' . JSignPdfHandler::VERSION . '.zip';
 		try {
-			$compressedFile = $this->getFolder($this->resource)->getFile($compressedFileName);
+			$compressedFile = $folder->getFile($compressedFileName);
 		} catch (\Throwable $th) {
-			$compressedFile = $this->getFolder($this->resource)->newFile($compressedFileName);
+			$compressedFile = $folder->newFile($compressedFileName);
 		}
 		$comporessedInternalFileName = $this->getDataDir() . '/' . $this->getInternalPathOfFile($compressedFile);
 		$url = 'https://github.com/intoolswetrust/jsignpdf/releases/download/JSignPdf_' . str_replace('.', '_', JSignPdfHandler::VERSION) . '/jsignpdf-' . JSignPdfHandler::VERSION . '.zip';
@@ -474,11 +484,11 @@ public function installPdftk(?bool $async = false): void {
 			$this->runAsync();
 			return;
 		}
-
+		$folder = $this->getEmptyFolder($this->resource);
 		try {
-			$file = $this->getFolder($this->resource)->getFile('pdftk.jar');
+			$file = $folder->getFile('pdftk.jar');
 		} catch (\Throwable $th) {
-			$file = $this->getFolder($this->resource)->newFile('pdftk.jar');
+			$file = $folder->newFile('pdftk.jar');
 		}
 		$fullPath = $this->getDataDir() . '/' . $this->getInternalPathOfFile($file);
 		$url = 'https://gitlab.com/api/v4/projects/5024297/packages/generic/pdftk-java/v' . self::PDFTK_VERSION . '/pdftk-all.jar';
@@ -534,7 +544,7 @@ public function installCfssl(?bool $async = false): void {
 	}
 
 	private function installCfsslByArchitecture(string $arcitecture): void {
-		$folder = $this->getFolder($this->resource);
+		$folder = $this->getEmptyFolder($this->resource);
 
 		$downloads = [
 			[
diff --git a/lib/Service/Install/SignSetupService.php b/lib/Service/Install/SignSetupService.php
index 4d208859b7..9c09ee3a99 100644
--- a/lib/Service/Install/SignSetupService.php
+++ b/lib/Service/Install/SignSetupService.php
@@ -262,6 +262,9 @@ private function getInstallPath(): string {
 	 * @throws \Exception
 	 */
 	private function getFolderIterator(string $folderToIterate): \RecursiveIteratorIterator {
+		if (!is_dir($folderToIterate)) {
+			throw new InvalidSignatureException('No such directory ' . $folderToIterate);
+		}
 		$dirItr = new \RecursiveDirectoryIterator(
 			$folderToIterate,
 			\RecursiveDirectoryIterator::SKIP_DOTS