diff --git a/packages/media-utils/src/utils/upload-media.ts b/packages/media-utils/src/utils/upload-media.ts
index ff3f718076512b..5d3986fba7a004 100644
--- a/packages/media-utils/src/utils/upload-media.ts
+++ b/packages/media-utils/src/utils/upload-media.ts
@@ -134,9 +134,16 @@ export function uploadMedia( {
 			// Reset to empty on failure.
 			setAndUpdateFiles( index, null );
 
-			let message;
-			if ( error instanceof Error ) {
-				message = error.message;
+			let message: string;
+			if (
+				typeof error === 'object' &&
+				error !== null &&
+				'message' in error
+			) {
+				message =
+					typeof error.message === 'string'
+						? error.message
+						: String( error.message );
 			} else {
 				message = sprintf(
 					// translators: %s: file name