diff --git a/.yarn/cache/@mittwald-api-client-commons-npm-4.356.0-af09335a67-ac41abd764.zip b/.yarn/cache/@mittwald-api-client-commons-npm-4.360.0-19744b8c19-d0f4e090d1.zip
similarity index 88%
rename from .yarn/cache/@mittwald-api-client-commons-npm-4.356.0-af09335a67-ac41abd764.zip
rename to .yarn/cache/@mittwald-api-client-commons-npm-4.360.0-19744b8c19-d0f4e090d1.zip
index b490ae9dc..0cc401013 100644
Binary files a/.yarn/cache/@mittwald-api-client-commons-npm-4.356.0-af09335a67-ac41abd764.zip and b/.yarn/cache/@mittwald-api-client-commons-npm-4.360.0-19744b8c19-d0f4e090d1.zip differ
diff --git a/.yarn/cache/@mittwald-api-client-npm-4.356.0-4214cd5b46-810efbe04a.zip b/.yarn/cache/@mittwald-api-client-npm-4.356.0-4214cd5b46-810efbe04a.zip
deleted file mode 100644
index 9e58f74f3..000000000
Binary files a/.yarn/cache/@mittwald-api-client-npm-4.356.0-4214cd5b46-810efbe04a.zip and /dev/null differ
diff --git a/.yarn/cache/@mittwald-api-client-npm-4.360.0-a9a6b86145-96ff226761.zip b/.yarn/cache/@mittwald-api-client-npm-4.360.0-a9a6b86145-96ff226761.zip
new file mode 100644
index 000000000..6ddca46e0
Binary files /dev/null and b/.yarn/cache/@mittwald-api-client-npm-4.360.0-a9a6b86145-96ff226761.zip differ
diff --git a/.yarn/cache/axios-npm-1.13.6-d50d919f38-72e94640e3.zip b/.yarn/cache/axios-npm-1.13.6-d50d919f38-72e94640e3.zip
deleted file mode 100644
index 8cdbcf49d..000000000
Binary files a/.yarn/cache/axios-npm-1.13.6-d50d919f38-72e94640e3.zip and /dev/null differ
diff --git a/.yarn/cache/axios-npm-1.16.0-77f999ccb9-93e8109681.zip b/.yarn/cache/axios-npm-1.16.0-77f999ccb9-93e8109681.zip
new file mode 100644
index 000000000..9e316e6ab
Binary files /dev/null and b/.yarn/cache/axios-npm-1.16.0-77f999ccb9-93e8109681.zip differ
diff --git a/.yarn/cache/follow-redirects-npm-1.15.11-ae7b2db266-20bf55e950.zip b/.yarn/cache/follow-redirects-npm-1.15.11-ae7b2db266-20bf55e950.zip
deleted file mode 100644
index dc1a208ce..000000000
Binary files a/.yarn/cache/follow-redirects-npm-1.15.11-ae7b2db266-20bf55e950.zip and /dev/null differ
diff --git a/.yarn/cache/follow-redirects-npm-1.16.0-816e4f62d9-e90dce4607.zip b/.yarn/cache/follow-redirects-npm-1.16.0-816e4f62d9-e90dce4607.zip
new file mode 100644
index 000000000..b6ca7b402
Binary files /dev/null and b/.yarn/cache/follow-redirects-npm-1.16.0-816e4f62d9-e90dce4607.zip differ
diff --git a/.yarn/cache/proxy-from-env-npm-2.1.0-ce678f045b-b106ad790f.zip b/.yarn/cache/proxy-from-env-npm-2.1.0-ce678f045b-b106ad790f.zip
new file mode 100644
index 000000000..b92f65eb1
Binary files /dev/null and b/.yarn/cache/proxy-from-env-npm-2.1.0-ce678f045b-b106ad790f.zip differ
diff --git a/src/commands/backup/download.tsx b/src/commands/backup/download.tsx
index 4ad43c3cf..3fd1e318a 100644
--- a/src/commands/backup/download.tsx
+++ b/src/commands/backup/download.tsx
@@ -159,8 +159,9 @@ export class Download extends ExecRenderBaseCommand<typeof Download, Result> {
 
     const downloadStep = p.addStep("downloading backup");
     const resp = await axios(backupExport.downloadURL, reqConfig);
+    const contentLength = this.getContentLength(resp.headers["content-length"]);
     const size = ByteQuantity.fromBytes(
-      parseInt(resp.headers["content-length"] || "0", 10),
+      Number.isFinite(contentLength) ? contentLength : 0,
     );
     let downloaded = ByteQuantity.fromBytes(0);
 
@@ -205,6 +206,22 @@ export class Download extends ExecRenderBaseCommand<typeof Download, Result> {
     return { outputFilename };
   }
 
+  protected getContentLength(contentLengthHeader: unknown): number {
+    if (typeof contentLengthHeader === "string") {
+      return parseInt(contentLengthHeader, 10);
+    }
+
+    if (Array.isArray(contentLengthHeader)) {
+      return parseInt(contentLengthHeader[0] || "0", 10);
+    }
+
+    if (typeof contentLengthHeader === "number") {
+      return contentLengthHeader;
+    }
+
+    return 0;
+  }
+
   protected getFilename(
     headers: RawAxiosResponseHeaders | AxiosResponseHeaders,
   ): string {
diff --git a/yarn.lock b/yarn.lock
index dc648eade..cc992dd9d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2551,12 +2551,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@mittwald/api-client-commons@npm:^4.356.0":
-  version: 4.356.0
-  resolution: "@mittwald/api-client-commons@npm:4.356.0"
+"@mittwald/api-client-commons@npm:^4.360.0":
+  version: 4.360.0
+  resolution: "@mittwald/api-client-commons@npm:4.360.0"
   dependencies:
     "@types/parse-path": ^7.0.3
-    axios: ^1.13.5
+    axios: ^1.15.2
     parse-path: ^7.1.0
     path-to-regexp: ^8.3.0
     type-fest: ^4.30.0
@@ -2567,22 +2567,22 @@ __metadata:
       optional: true
     "@mittwald/react-use-promise":
       optional: true
-  checksum: ac41abd7640c1e015f180cd8fb81d155c033e851580eb7541b285552a72db8b694a0c140a8b9ac0f21cda326a27f9c9f0fd9b843859e5d3a3fb7123de7e2c6d1
+  checksum: d0f4e090d1deb255c25c63b322e64eae9292bd6124bb220b09523309f9c7518a85f88fa33e06cc9e18cb7f78d86bf0a0596dfc8bc6bbc85a156a7d79f64a33b8
   languageName: node
   linkType: hard
 
 "@mittwald/api-client@npm:^4.131.0":
-  version: 4.356.0
-  resolution: "@mittwald/api-client@npm:4.356.0"
+  version: 4.360.0
+  resolution: "@mittwald/api-client@npm:4.360.0"
   dependencies:
-    "@mittwald/api-client-commons": ^4.356.0
+    "@mittwald/api-client-commons": ^4.360.0
     browser-or-node: ^3.0.0
   peerDependencies:
     "@mittwald/react-use-promise": ^2.6.0
   peerDependenciesMeta:
     "@mittwald/react-use-promise":
       optional: true
-  checksum: 810efbe04a23cc20de3f4bbec1c74c33aaf4677a96f22bfe74f1f5d00983ce443b79f95beeb3890cb939a4d5fbf5f593a9a676cdcf99962ad1b69a04b263a690
+  checksum: 96ff226761cbc0e43de97fc694267d837f83fb098a5da4f8d01ce68d6dc53e8bf9c11ae8fb2e95b177a5190fcdf86ebdd09d1370e2ee58c6439bae3d6013980a
   languageName: node
   linkType: hard
 
@@ -4769,14 +4769,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"axios@npm:^1.13.5":
-  version: 1.13.6
-  resolution: "axios@npm:1.13.6"
+"axios@npm:^1.15.2":
+  version: 1.16.0
+  resolution: "axios@npm:1.16.0"
   dependencies:
-    follow-redirects: ^1.15.11
+    follow-redirects: ^1.16.0
     form-data: ^4.0.5
-    proxy-from-env: ^1.1.0
-  checksum: 72e94640e34aa9b591a47a9cc1798a1e18f179e15e39276514dd73f6d910981bdb2117c649da858bd72fc34d91db4f84318f88c8d306e395cd4ef5d6f142ab70
+    proxy-from-env: ^2.1.0
+  checksum: 93e810968167fea59750d28f458e6860973a573c14bd60fe57ee07b5241f4c16991b149ae9ce65d79765081e3004743c9e158c438edba75af6f4612197e6834b
   languageName: node
   linkType: hard
 
@@ -6444,13 +6444,13 @@ __metadata:
   languageName: node
   linkType: hard
 
-"follow-redirects@npm:^1.15.11":
-  version: 1.15.11
-  resolution: "follow-redirects@npm:1.15.11"
+"follow-redirects@npm:^1.16.0":
+  version: 1.16.0
+  resolution: "follow-redirects@npm:1.16.0"
   peerDependenciesMeta:
     debug:
       optional: true
-  checksum: 20bf55e9504f59e6cc3743ba27edb2ebf41edea1baab34799408f2c050f73f0c612728db21c691276296d2795ea8a812dc532a98e8793619fcab91abe06d017f
+  checksum: e90dce4607b1f6b8b9883287f912585573c19088209ad82341d550a795b4ba514522b73b1b340cf618279df27975cd46504d09149be60291ba6767384c1fd8f8
   languageName: node
   linkType: hard
 
@@ -9633,6 +9633,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"proxy-from-env@npm:^2.1.0":
+  version: 2.1.0
+  resolution: "proxy-from-env@npm:2.1.0"
+  checksum: b106ad790f26d47ba4791af3fe8cba5c8d35d85020119c82c05b413eb11b3ab97d2393ecaed51bca97c2788fa256408283dfeb4d970b2ebcae6702310f064e7e
+  languageName: node
+  linkType: hard
+
 "pump@npm:^3.0.0":
   version: 3.0.3
   resolution: "pump@npm:3.0.3"