diff --git a/scm-ui/src/admin/plugins/components/MultiPluginActionModal.js b/scm-ui/src/admin/plugins/components/MultiPluginActionModal.js
index a2a127d33f..394b7e48c9 100644
--- a/scm-ui/src/admin/plugins/components/MultiPluginActionModal.js
+++ b/scm-ui/src/admin/plugins/components/MultiPluginActionModal.js
@@ -97,7 +97,16 @@ class MultiPluginActionModal extends React.Component<Props, State> {
       loading: true
     });
 
-    apiClient.post(pendingPlugins._links.cancel.href).then(() => this.reload());
+    apiClient
+      .post(pendingPlugins._links.cancel.href)
+      .then(() => this.reload())
+      .catch(error => {
+        this.setState({
+          success: false,
+          loading: false,
+          error: error
+        });
+      });
   };
 
   updateAll = () => {
@@ -239,6 +248,7 @@ class MultiPluginActionModal extends React.Component<Props, State> {
 
   renderBody = () => {
     const { actionType } = this.props;
+    const { error } = this.state;
     return (
       <>
         <div className="media">
@@ -247,6 +257,11 @@ class MultiPluginActionModal extends React.Component<Props, State> {
             {this.renderModalContent()}
           </div>
         </div>
+        {!!error && (
+          <div className="media">
+            <ErrorNotification error={error} />
+          </div>
+        )}
         {actionType === MultiPluginActionType.EXECUTE_PENDING && (
           <div className="media">{this.renderNotifications()}</div>
         )}
diff --git a/scm-ui/src/admin/plugins/components/PluginModal.js b/scm-ui/src/admin/plugins/components/PluginModal.js
index b15a068fa2..85e0f078d6 100644
--- a/scm-ui/src/admin/plugins/components/PluginModal.js
+++ b/scm-ui/src/admin/plugins/components/PluginModal.js
@@ -121,6 +121,7 @@ class PluginModal extends React.Component<Props, State> {
       .catch(error => {
         this.setState({
           loading: false,
+          success: false,
           error: error
         });
       });
diff --git a/scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginManager.java b/scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginManager.java
index 4b4db3a162..07accbcc76 100644
--- a/scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginManager.java
+++ b/scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginManager.java
@@ -288,7 +288,7 @@ public class DefaultPluginManager implements PluginManager {
     pendingInstallQueue.forEach(PendingPluginInstallation::cancel);
     pendingUninstallQueue.clear();
     pendingInstallQueue.clear();
-    getInstalled().forEach(p -> p.setUninstallable(isUninstallable(p)));
+    updateMayUninstallFlag();
   }
 
   @Override
diff --git a/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginInstallation.java b/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginInstallation.java
index 2f5d388db2..f2a8a4d633 100644
--- a/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginInstallation.java
+++ b/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginInstallation.java
@@ -30,7 +30,7 @@ class PendingPluginInstallation {
       Files.delete(file);
       plugin.cancelInstallation();
     } catch (IOException ex) {
-      throw new PluginFailedToCancelInstallationException("failed to cancel installation of plugin " + name, ex);
+      throw new PluginFailedToCancelInstallationException("failed to cancel plugin installation ", name, ex);
     }
   }
 }
diff --git a/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginUninstallation.java b/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginUninstallation.java
index 8d5a44d60a..7cbbecd151 100644
--- a/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginUninstallation.java
+++ b/scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginUninstallation.java
@@ -26,7 +26,7 @@ class PendingPluginUninstallation {
       Files.delete(uninstallFile);
       plugin.setMarkedForUninstall(false);
     } catch (IOException ex) {
-      throw new PluginFailedToCancelInstallationException("failed to cancel uninstallation of plugin " + name, ex);
+      throw new PluginFailedToCancelInstallationException("failed to cancel uninstallation", name, ex);
     }
   }
 }
diff --git a/scm-webapp/src/main/java/sonia/scm/plugin/PluginFailedToCancelInstallationException.java b/scm-webapp/src/main/java/sonia/scm/plugin/PluginFailedToCancelInstallationException.java
index e3d6c123d6..1be5ecdcf3 100644
--- a/scm-webapp/src/main/java/sonia/scm/plugin/PluginFailedToCancelInstallationException.java
+++ b/scm-webapp/src/main/java/sonia/scm/plugin/PluginFailedToCancelInstallationException.java
@@ -1,7 +1,16 @@
 package sonia.scm.plugin;
 
-public class PluginFailedToCancelInstallationException extends RuntimeException {
-  public PluginFailedToCancelInstallationException(String message, Throwable cause) {
-    super(message, cause);
+import sonia.scm.ExceptionWithContext;
+
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+
+public class PluginFailedToCancelInstallationException extends ExceptionWithContext {
+  public PluginFailedToCancelInstallationException(String message, String name, Exception cause) {
+    super(entity("plugin", name).build(), message, cause);
+  }
+
+  @Override
+  public String getCode() {
+    return "65RdZ5atX1";
   }
 }
diff --git a/scm-webapp/src/main/resources/locales/de/plugins.json b/scm-webapp/src/main/resources/locales/de/plugins.json
index 9c5bb3f5f5..f7ba2e9adf 100644
--- a/scm-webapp/src/main/resources/locales/de/plugins.json
+++ b/scm-webapp/src/main/resources/locales/de/plugins.json
@@ -175,6 +175,10 @@
     "40RaYIeeR1": {
       "displayName": "Es wurden keine Änderungen durchgeführt",
       "description": "Das Repository wurde nicht verändert. Daher konnte kein neuer Commit erzeugt werden."
+    },
+    "65RdZ5atX1": {
+      "displayName": "Fehler beim Löschen von Plugin-Dateien",
+      "description": "Einige Dateien für die Plugin-Deinstallation konnten nicht gelöscht werden. Dieses kann zu Inkonsistenzen führen, so dass der SCM-Manager nicht mehr korrekt starten kann. Bitte prüfen Sie die Logs und bereinigen Sie das Plugin-Verzeichnis des SCM-Managers manuell."
     }
   },
   "namespaceStrategies": {
diff --git a/scm-webapp/src/main/resources/locales/en/plugins.json b/scm-webapp/src/main/resources/locales/en/plugins.json
index 1ffffd73b7..a12ed3a194 100644
--- a/scm-webapp/src/main/resources/locales/en/plugins.json
+++ b/scm-webapp/src/main/resources/locales/en/plugins.json
@@ -175,6 +175,10 @@
     "40RaYIeeR1": {
       "displayName": "No changes were made",
       "description": "No changes were made to the files of the repository. Therefor no new commit could be created."
+    },
+    "65RdZ5atX1": {
+      "displayName": "Error removing plugin files",
+      "description": "Some files to cancel the plugin (un)installation could not be deleted. This can lead to inconsistencies so that the SCM-Manager cannot restart properly. Please check the logs and clean up the plugin folder manually."
     }
   },
   "namespaceStrategies": {