diff --git a/lib/Service/ConfigService.php b/lib/Service/ConfigService.php
index 006565dea..755cc0ce1 100644
--- a/lib/Service/ConfigService.php
+++ b/lib/Service/ConfigService.php
@@ -230,4 +230,12 @@ class ConfigService {
 
 		return $this->config->getUserValue($userId ?? $this->getUserId(), 'deck', 'attachment_folder', '/Deck');
 	}
+
+	public function setAttachmentFolder(?string $userId = null, string $path): void {
+		if ($userId === null && $this->getUserId() === null) {
+			throw new NoPermissionException('Must be logged in get the attachment folder');
+		}
+
+		$this->config->setUserValue($userId ?? $this->getUserId(), 'deck', 'attachment_folder', $path);
+	}
 }
diff --git a/lib/Service/FilesAppService.php b/lib/Service/FilesAppService.php
index 09e0c16da..80b82ee65 100644
--- a/lib/Service/FilesAppService.php
+++ b/lib/Service/FilesAppService.php
@@ -31,6 +31,7 @@ use OCA\Deck\Sharing\DeckShareProvider;
 use OCA\Deck\StatusException;
 use OCP\AppFramework\Http\StreamResponse;
 use OCP\Constants;
+use OCP\Files\Folder;
 use OCP\Files\IMimeTypeDetector;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotFoundException;
@@ -186,10 +187,20 @@ class FilesAppService implements IAttachmentService, ICustomAttachmentService {
 		$userFolder = $this->rootFolder->getUserFolder($this->userId);
 		try {
 			$folder = $userFolder->get($this->configService->getAttachmentFolder());
-		} catch (NotFoundException $e) {
+		} catch (NotFoundException) {
 			$folder = $userFolder->newFolder($this->configService->getAttachmentFolder());
 		}
 
+		if ($folder->isShared()) {
+			$folderName = $userFolder->getNonExistingName($this->configService->getAttachmentFolder());
+			$folder = $userFolder->newFolder($folderName);
+			$this->configService->setAttachmentFolder($this->userId, $folderName);
+		}
+
+		if (!$folder instanceof Folder || $folder->isShared()) {
+			throw new NotFoundException('No target folder found');
+		}
+
 		$fileName = $folder->getNonExistingName($fileName);
 		$target = $folder->newFile($fileName);
 		$content = fopen($file['tmp_name'], 'rb');