diff --git a/lib/Chat/AutoComplete/SearchPlugin.php b/lib/Chat/AutoComplete/SearchPlugin.php
index dcb303708de..284aa180c51 100644
--- a/lib/Chat/AutoComplete/SearchPlugin.php
+++ b/lib/Chat/AutoComplete/SearchPlugin.php
@@ -52,7 +52,11 @@ public function setContext(array $context): void {
 	#[\Override]
 	public function search($search, $limit, $offset, ISearchResult $searchResult): bool {
 		if ($this->room->getObjectType() === 'file') {
-			$usersWithFileAccess = $this->util->getUsersWithAccessFile($this->room->getObjectId());
+			if ($this->userId === null) {
+				$usersWithFileAccess = $this->util->canGuestsAccessFile($this->room->getObjectId());
+			} else {
+				$usersWithFileAccess = $this->util->getUsersWithAccessFile($this->room->getObjectId(), $this->userId);
+			}
 			if (!empty($usersWithFileAccess)) {
 				$users = [];
 				foreach ($usersWithFileAccess as $userId) {
diff --git a/lib/Controller/FilesIntegrationController.php b/lib/Controller/FilesIntegrationController.php
index c5d276ed1d3..67928369a41 100644
--- a/lib/Controller/FilesIntegrationController.php
+++ b/lib/Controller/FilesIntegrationController.php
@@ -104,7 +104,7 @@ public function getRoomByFileId(string $fileId): DataResponse {
 			throw new OCSNotFoundException($this->l->t('File is not shared, or shared but not with the user'));
 		}
 
-		$users = $this->util->getUsersWithAccessFile($fileId);
+		$users = $this->util->getUsersWithAccessFile($fileId, $currentUser->getUID());
 		if (count($users) <= 1 && !$this->util->canGuestsAccessFile($fileId)) {
 			throw new OCSNotFoundException($this->l->t('File is not shared, or shared but not with the user'));
 		}
diff --git a/lib/Files/Util.php b/lib/Files/Util.php
index 0f98479e5d2..1632b30202e 100644
--- a/lib/Files/Util.php
+++ b/lib/Files/Util.php
@@ -35,15 +35,15 @@ public function __construct(
 	/**
 	 * @return string[]
 	 */
-	public function getUsersWithAccessFile(string $fileId): array {
+	public function getUsersWithAccessFile(string $fileId, string $userId): array {
 		if (!isset($this->accessLists[$fileId])) {
-			$nodes = $this->rootFolder->getById((int)$fileId);
+			$userFolder = $this->rootFolder->getUserFolder($userId);
+			$node = $userFolder->getFirstNodeById((int)$fileId);
 
-			if (empty($nodes)) {
+			if ($node === null) {
 				return [];
 			}
 
-			$node = array_shift($nodes);
 			$accessList = $this->shareManager->getAccessList($node);
 			$accessList['users'] ??= [];
 			if (!$node->getStorage()->instanceOfStorage(SharedStorage::class)) {
@@ -64,18 +64,17 @@ public function getUsersWithAccessFile(string $fileId): array {
 	}
 
 	public function canUserAccessFile(string $fileId, string $userId): bool {
-		return \in_array($userId, $this->getUsersWithAccessFile($fileId), true);
+		return \in_array($userId, $this->getUsersWithAccessFile($fileId, $userId), true);
 	}
 
 	public function canGuestsAccessFile(string $fileId): bool {
 		if (!isset($this->publicAccessLists[$fileId])) {
-			$nodes = $this->rootFolder->getById((int)$fileId);
+			$node = $this->rootFolder->getFirstNodeById((int)$fileId);
 
-			if (empty($nodes)) {
+			if ($node === null) {
 				return false;
 			}
 
-			$node = array_shift($nodes);
 			$accessList = $this->shareManager->getAccessList($node, false);
 			$this->publicAccessLists[$fileId] = $accessList['public'] ?? false;
 		}
diff --git a/tests/integration/features/chat-2/mentions.feature b/tests/integration/features/chat-2/mentions.feature
index 66e935a7f38..012809675eb 100644
--- a/tests/integration/features/chat-2/mentions.feature
+++ b/tests/integration/features/chat-2/mentions.feature
@@ -573,8 +573,11 @@ Feature: chat-2/mentions
     And user "guest" joins room "file last share room" with 200 (v4)
     And user "participant2" is not participant of room "file last share room" (v4)
     When user "participant3" sends message "hi @participant2" to room "file last share room" with 201
+    And user "participant2" is participant of room "file last share room" (v4)
+    And user "participant2" removes themselves from room "file last share room" with 200 (v4)
+    And user "participant2" is not participant of room "file last share room" (v4)
     And user "guest" sends message "hello @participant2" to room "file last share room" with 201
-    Then user "participant2" is not participant of room "file last share room" (v4)
+    Then user "participant2" is participant of room "file last share room" (v4)
 
   Scenario: mention a participant without access to the file but joined in a room for a file shared by link
     Given user "participant1" shares "welcome.txt" with user "participant2" with OCS 100