diff --git a/PDMI/store/templates/store/upload.html b/PDMI/store/templates/store/upload.html
index 7ad61ba..41e4474 100644
--- a/PDMI/store/templates/store/upload.html
+++ b/PDMI/store/templates/store/upload.html
@@ -8,6 +8,9 @@
 {% block body %}
 <main>
     <div class="container pt-5">
+        <div class="alert alert-danger alert-dismissible fade show" id="errorZone" style="display:none;">
+            <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
+        </div>
         <form class="dropzone" enctype="multipart/form-data" method="post" id="multiFileUpload">
             <div class="fallback">
                 <input type="file" name="file" id="file" multiple />
@@ -64,7 +67,8 @@ $('#multiFileUpload').dropzone({
         });
         this.on("error", function(file, message) {
             console.log(message);
-            this.removeFile(file);
+            $('#errorZone').append(message.error);
+            $('#errorZone').show();
         });
         this.on('sending', function(file, xhr, formData) {
             xhr.setRequestHeader("X-CSRFToken", csrftoken)
diff --git a/PDMI/store/views.py b/PDMI/store/views.py
index f6173e9..c6c9705 100644
--- a/PDMI/store/views.py
+++ b/PDMI/store/views.py
@@ -9,10 +9,12 @@ from .response import response_mimetype, JsonResponse
 from .models import Module, Version, Dependency
 from PDMI import settings
 from packaging.specifiers import SpecifierSet
+from django.http import HttpResponse
 import os
 import zipfile
 import toml
 import shutil
+import magic
 
 
 class SignUpView(BSModalCreateView):
@@ -44,6 +46,11 @@ class UploadView(LoginRequiredMixin, FormView):
                 with open(zip_path, "wb+") as f:    # Writing archive
                     for chunk in file.chunks():
                         f.write(chunk)
+                if magic.from_file(zip_path, mime=True) != 'application/zip':
+                    print(magic.from_file(zip_path))
+                    os.remove(zip_path)
+                    return JsonResponse({'error': 'You must upload a zip archive.'}, status=500)
+
                 with zipfile.ZipFile(zip_path, 'r') as zip:  # Unzip archive
                     zip.extractall(extract_path)
                 with open(os.path.join(extract_path, 'infos.toml'), 'r') as f:
@@ -61,7 +68,7 @@ class UploadView(LoginRequiredMixin, FormView):
                     module = Module(name=module_info['name'].lower(),
                                     desc=module_info['description'],
                                     creator=request.user)
-                if Version.objects.filter(module=module, ver=module_info['version']).count() > 0:
+                if Version.objects.filter(module=module, ver=module_info['version']).exists():
                     # If version already exists, edit existing version
                     version = Version.objects.get(
                         module=module, ver=module_info['version'])
@@ -77,7 +84,7 @@ class UploadView(LoginRequiredMixin, FormView):
                 version.save()
                 for dependency in module_info['dependencies']:
                     if not Dependency.objects.filter(version=version, dep_module=dependency,
-                                  dep_version=module_info['dependencies'][dependency]).count() > 0:
+                                  dep_version=module_info['dependencies'][dependency]).exists():
                         dep = Dependency(version=version, dep_module=dependency,
                                         dep_version=module_info['dependencies'][dependency])
                         dep.save()
diff --git a/Pipfile b/Pipfile
index fd3fc73..d4de018 100644
--- a/Pipfile
+++ b/Pipfile
@@ -9,6 +9,7 @@ verify_ssl = true
 django = "*"
 django-widget-tweaks = "*"
 django-bootstrap-modal-forms = "*"
+python-magic = "*"
 
 [requires]
 python_version = "3.8"