diff --git a/apps/api/src/group-files/ocis-webdav.ts b/apps/api/src/group-files/ocis-webdav.ts
index 65c75ef..5d4707f 100644
--- a/apps/api/src/group-files/ocis-webdav.ts
+++ b/apps/api/src/group-files/ocis-webdav.ts
@@ -144,7 +144,14 @@ export class OcisWebdavClient {
 
   /** MKCOL the group folder; 405 (already exists) is fine. */
   private async ensureGroupFolder(groupId: string): Promise<void> {
-    const url = `${this.config.webdavUrl}/remote.php/dav/files/${encodeURIComponent(this.config.user)}/hub-groups/${encodeURIComponent(groupId)}`;
+    const base = `${this.config.webdavUrl}/remote.php/dav/files/${encodeURIComponent(this.config.user)}`;
+    // MKCOL returns 409 when the parent collection is missing — create the
+    // hub-groups root (405 = already exists), then the per-group folder.
+    const root = await this.fetcher(`${base}/hub-groups`, { method: "MKCOL", headers: this.authHeaders() });
+    if (!root.ok && root.status !== 405) {
+      throw new Error(`oCIS folder creation failed with ${root.status}`);
+    }
+    const url = `${base}/hub-groups/${encodeURIComponent(groupId)}`;
     const response = await this.fetcher(url, { method: "MKCOL", headers: this.authHeaders() });
     if (response.ok || response.status === 405) return;
     throw new Error(`oCIS folder creation failed with ${response.status}`);