diff --git a/src/system.js b/src/system.js
index db4eec96c..828b3bd06 100644
--- a/src/system.js
+++ b/src/system.js
@@ -88,7 +88,7 @@ async function getSwaps() {
 }
 
 async function getDisks() {
-    let [dfError, dfEntries] = await safe(df.disks());
+    const [dfError, dfEntries] = await safe(df.disks());
     if (dfError) throw new BoxError(BoxError.FS_ERROR, `Error running df: ${dfError.message}`);
 
     const disks = {}; // by file system