diff --git a/backend/src/routes/admin.ts b/backend/src/routes/admin.ts
index 0246993..45177fc 100644
--- a/backend/src/routes/admin.ts
+++ b/backend/src/routes/admin.ts
@@ -3,7 +3,7 @@ import { and, eq, inArray, isNull, sql } from "drizzle-orm";
 import multipart from "@fastify/multipart";
 import { DeleteObjectCommand, GetObjectCommand, PutObjectCommand } from "@aws-sdk/client-s3";
 import { randomUUID } from "node:crypto";
-import { createReadStream, createWriteStream } from "node:fs";
+import { createReadStream, createWriteStream, openAsBlob } from "node:fs";
 import { stat, unlink } from "node:fs/promises";
 import { pipeline } from "node:stream/promises";
 
@@ -469,6 +469,7 @@ export default async function adminRoutes(server: FastifyInstance) {
         currentUser: { id: string; email: string },
         source: { archiveStoragePath: string } | { exportData: TenantFullExport }
     ) => {
+        let temporaryArchivePath: string | null = null;
         try {
             await server.db
                 .update(tenantExportJobs)
@@ -499,8 +500,10 @@ export default async function adminRoutes(server: FastifyInstance) {
                 }));
                 if (!object.Body) throw new Error("Importarchiv konnte nicht aus dem Speicher gelesen werden");
 
-                const archiveBuffer = Buffer.from(await object.Body.transformToByteArray());
-                result = await importTenantFullExportArchive(server, archiveBuffer, { onProgress });
+                temporaryArchivePath = `${process.env.TMPDIR || "/tmp"}/fedeo-tenant-import-${randomUUID()}.zip`;
+                await pipeline(object.Body as NodeJS.ReadableStream, createWriteStream(temporaryArchivePath, { flags: "wx" }));
+                const archive = await openAsBlob(temporaryArchivePath);
+                result = await importTenantFullExportArchive(server, archive, { onProgress });
             } else {
                 result = await importTenantFullExport(server, source.exportData, { onProgress });
             }
@@ -532,6 +535,11 @@ export default async function adminRoutes(server: FastifyInstance) {
                 })
                 .where(eq(tenantExportJobs.id, jobId));
         } finally {
+            if (temporaryArchivePath) {
+                await unlink(temporaryArchivePath).catch((cleanupError) => {
+                    console.error("ERROR cleanup temporary tenant import archive:", cleanupError);
+                });
+            }
             if ("archiveStoragePath" in source) {
                 await s3.send(new DeleteObjectCommand({
                     Bucket: secrets.S3_BUCKET,
diff --git a/backend/src/utils/tenantFullExport.ts b/backend/src/utils/tenantFullExport.ts
index f8b0dc5..347b6c7 100644
--- a/backend/src/utils/tenantFullExport.ts
+++ b/backend/src/utils/tenantFullExport.ts
@@ -982,10 +982,10 @@ export const importTenantFullExport = async (
 
 export const importTenantFullExportArchive = async (
     server: FastifyInstance,
-    archiveBuffer: Buffer,
+    archive: Buffer | Blob,
     options: ImportOptions = {}
 ): Promise<ImportResult> => {
-    const reader = new ZipReader(new BlobReader(new Blob([archiveBuffer])))
+    const reader = new ZipReader(new BlobReader(archive instanceof Blob ? archive : new Blob([archive])))
 
     try {
         const entries = await reader.getEntries()