diff --git a/spiffworkflow-frontend/src/routes/ProcessModelShow.tsx b/spiffworkflow-frontend/src/routes/ProcessModelShow.tsx
index 5da047685..0a217f70b 100644
--- a/spiffworkflow-frontend/src/routes/ProcessModelShow.tsx
+++ b/spiffworkflow-frontend/src/routes/ProcessModelShow.tsx
@@ -492,6 +492,7 @@ export default function ProcessModelShow() {
         open={showFileUploadModal}
         modalHeading="Upload File"
         primaryButtonText="Upload"
+        primaryButtonDisabled={filesToUpload === null}
         secondaryButtonText="Cancel"
         onSecondarySubmit={handleFileUploadCancel}
         onRequestClose={handleFileUploadCancel}