diff --git a/app/src/main/java/eu/faircode/email/ActivityBase.java b/app/src/main/java/eu/faircode/email/ActivityBase.java
index d651df7c32..9214aabd90 100644
--- a/app/src/main/java/eu/faircode/email/ActivityBase.java
+++ b/app/src/main/java/eu/faircode/email/ActivityBase.java
@@ -511,10 +511,7 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
             if (TextUtils.isEmpty(fname))
                 return uri;
 
-            File dir = new File(getFilesDir(), "shared");
-            if (!dir.exists())
-                dir.mkdir();
-
+            File dir = Helper.ensureExists(new File(getFilesDir(), "shared"));
             File file = new File(dir, fname);
 
             Log.i("Copying shared file to " + file);
diff --git a/app/src/main/java/eu/faircode/email/ActivityEML.java b/app/src/main/java/eu/faircode/email/ActivityEML.java
index 7ec434f4c6..e3e10580fd 100644
--- a/app/src/main/java/eu/faircode/email/ActivityEML.java
+++ b/app/src/main/java/eu/faircode/email/ActivityEML.java
@@ -182,10 +182,7 @@ public class ActivityEML extends ActivityBase {
                         if (uri == null)
                             throw new FileNotFoundException();
 
-                        File dir = new File(context.getFilesDir(), "shared");
-                        if (!dir.exists())
-                            dir.mkdir();
-
+                        File dir = Helper.ensureExists(new File(context.getFilesDir(), "shared"));
                         File file = new File(dir, "email.eml");
 
                         Helper.copy(context, uri, file);
diff --git a/app/src/main/java/eu/faircode/email/AdapterCertificate.java b/app/src/main/java/eu/faircode/email/AdapterCertificate.java
index c5bbb66eb9..6e7f949f46 100644
--- a/app/src/main/java/eu/faircode/email/AdapterCertificate.java
+++ b/app/src/main/java/eu/faircode/email/AdapterCertificate.java
@@ -132,10 +132,7 @@ public class AdapterCertificate extends RecyclerView.Adapter<AdapterCertificate.
                             if (certificate == null)
                                 return null;
 
-                            File dir = new File(context.getFilesDir(), "shared");
-                            if (!dir.exists())
-                                dir.mkdir();
-
+                            File dir = Helper.ensureExists(new File(context.getFilesDir(), "shared"));
                             String name = Helper.sanitizeFilename(certificate.email);
                             File file = new File(dir, name + ".pem");
                             Helper.writeText(file, certificate.getPem());
diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 9ffad657da..39409d8ca7 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -3757,9 +3757,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                             response.setMethod(Method.REPLY);
                             response.addEvent(ev);
 
-                            File dir = new File(context.getFilesDir(), "calendar");
-                            if (!dir.exists())
-                                dir.mkdir();
+                            File dir = Helper.ensureExists(new File(context.getFilesDir(), "calendar"));
                             File ics = new File(dir, message.id + ".ics");
                             response.write(ics);
 
@@ -6756,10 +6754,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                             element.attr("x-computed", computed);
                     }
 
-                    File dir = new File(context.getFilesDir(), "shared");
-                    if (!dir.exists())
-                        dir.mkdir();
-
+                    File dir = Helper.ensureExists(new File(context.getFilesDir(), "shared"));
                     File share = new File(dir, message.id + ".txt");
                     Helper.writeText(share, d.html());
 
diff --git a/app/src/main/java/eu/faircode/email/ContactInfo.java b/app/src/main/java/eu/faircode/email/ContactInfo.java
index 9e7cf814e7..96bbd518d5 100644
--- a/app/src/main/java/eu/faircode/email/ContactInfo.java
+++ b/app/src/main/java/eu/faircode/email/ContactInfo.java
@@ -340,9 +340,7 @@ public class ContactInfo {
                 final String domain = d.toLowerCase(Locale.ROOT);
                 final String email = info.email.toLowerCase(Locale.ROOT);
 
-                File dir = new File(context.getFilesDir(), "favicons");
-                if (!dir.exists())
-                    dir.mkdir();
+                File dir = Helper.ensureExists(new File(context.getFilesDir(), "favicons"));
 
                 try {
                     // check cache
@@ -511,10 +509,7 @@ public class ContactInfo {
         // Generated
         boolean identicon = false;
         if (info.bitmap == null && generated && !TextUtils.isEmpty(info.email)) {
-            File dir = new File(context.getFilesDir(), "generated");
-            if (!dir.exists())
-                dir.mkdir();
-
+            File dir = Helper.ensureExists(new File(context.getFilesDir(), "generated"));
             File[] files = dir.listFiles(new FilenameFilter() {
                 @Override
                 public boolean accept(File file, String name) {
diff --git a/app/src/main/java/eu/faircode/email/EntityAttachment.java b/app/src/main/java/eu/faircode/email/EntityAttachment.java
index d7fcf0b999..c87506f9f3 100644
--- a/app/src/main/java/eu/faircode/email/EntityAttachment.java
+++ b/app/src/main/java/eu/faircode/email/EntityAttachment.java
@@ -150,9 +150,7 @@ public class EntityAttachment {
     }
 
     static File getFile(Context context, long id, String name) {
-        File dir = new File(getRoot(context), "attachments");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(getRoot(context), "attachments"));
         String filename = Long.toString(id);
         if (!TextUtils.isEmpty(name))
             filename += "." + Helper.sanitizeFilename(name);
diff --git a/app/src/main/java/eu/faircode/email/EntityMessage.java b/app/src/main/java/eu/faircode/email/EntityMessage.java
index 6455221060..c6169f6a13 100644
--- a/app/src/main/java/eu/faircode/email/EntityMessage.java
+++ b/app/src/main/java/eu/faircode/email/EntityMessage.java
@@ -577,9 +577,7 @@ public class EntityMessage implements Serializable {
     }
 
     static File getFile(Context context, Long id) {
-        File dir = new File(context.getFilesDir(), "messages");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(context.getFilesDir(), "messages"));
         return new File(dir, id.toString());
     }
 
@@ -588,16 +586,12 @@ public class EntityMessage implements Serializable {
     }
 
     File getFile(Context context, int revision) {
-        File dir = new File(context.getFilesDir(), "revision");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(context.getFilesDir(), "revision"));
         return new File(dir, id + "." + revision);
     }
 
     File getRefFile(Context context) {
-        File dir = new File(context.getFilesDir(), "references");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(context.getFilesDir(), "references"));
         return new File(dir, id.toString());
     }
 
@@ -606,9 +600,7 @@ public class EntityMessage implements Serializable {
     }
 
     static File getRawFile(Context context, Long id) {
-        File dir = new File(context.getFilesDir(), "raw");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(context.getFilesDir(), "raw"));
         return new File(dir, id + ".eml");
     }
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentCompose.java b/app/src/main/java/eu/faircode/email/FragmentCompose.java
index 05701992f2..049251b202 100644
--- a/app/src/main/java/eu/faircode/email/FragmentCompose.java
+++ b/app/src/main/java/eu/faircode/email/FragmentCompose.java
@@ -2412,7 +2412,7 @@ public class FragmentCompose extends FragmentBase {
         if (s > 1 && s <= edit.length() &&
                 edit.charAt(s - 1) == '\n' &&
                 edit.charAt(s - 2) != '\n' &&
-                (s == edit.length() || edit.charAt(s) == '\n') )
+                (s == edit.length() || edit.charAt(s) == '\n'))
             etBody.setSelection(s - 1, s - 1);
 
         Pair<Integer, Integer> paragraph = StyleHelper.getParagraph(etBody);
@@ -3112,9 +3112,7 @@ public class FragmentCompose extends FragmentBase {
                 });
                 snackbar.show();
             } else {
-                File dir = new File(context.getFilesDir(), "photo");
-                if (!dir.exists())
-                    dir.mkdir();
+                File dir = Helper.ensureExists(new File(context.getFilesDir(), "photo"));
                 File file = new File(dir, working + ".jpg");
                 try {
                     photoURI = FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID, file);
@@ -3410,9 +3408,7 @@ public class FragmentCompose extends FragmentBase {
                     throw new IllegalArgumentException(context.getString(R.string.title_from_missing));
 
                 // Create files
-                File tmp = new File(context.getFilesDir(), "encryption");
-                if (!tmp.exists())
-                    tmp.mkdir();
+                File tmp = Helper.ensureExists(new File(context.getFilesDir(), "encryption"));
                 File input = new File(tmp, draft.id + "_" + session + ".pgp_input");
                 File output = new File(tmp, draft.id + "_" + session + ".pgp_output");
 
@@ -3759,9 +3755,7 @@ public class FragmentCompose extends FragmentBase {
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
                 boolean check_certificate = prefs.getBoolean("check_certificate", true);
 
-                File tmp = new File(context.getFilesDir(), "encryption");
-                if (!tmp.exists())
-                    tmp.mkdir();
+                File tmp = Helper.ensureExists(new File(context.getFilesDir(), "encryption"));
 
                 DB db = DB.getInstance(context);
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index 832a40fd5c..3c51ced26e 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -8113,9 +8113,7 @@ public class FragmentMessages extends FragmentBase
                 OutputStream out = null;
                 boolean inline = false;
 
-                File tmp = new File(context.getFilesDir(), "encryption");
-                if (!tmp.exists())
-                    tmp.mkdir();
+                File tmp = Helper.ensureExists(new File(context.getFilesDir(), "encryption"));
                 File plain = new File(tmp, message.id + ".pgp_out");
 
                 // Find encrypted data
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index c0c4ea2483..34caa376fb 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -1108,11 +1108,8 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
                                 ? context.getExternalFilesDir(null)
                                 : context.getFilesDir());
 
-                        source = new File(source, "attachments");
-                        target = new File(target, "attachments");
-
-                        source.mkdirs();
-                        target.mkdirs();
+                        source = Helper.ensureExists(new File(source, "attachments"));
+                        target = Helper.ensureExists(new File(target, "attachments"));
 
                         File[] attachments = source.listFiles();
                         if (attachments != null)
diff --git a/app/src/main/java/eu/faircode/email/Helper.java b/app/src/main/java/eu/faircode/email/Helper.java
index dc2e938126..30e687ec5f 100644
--- a/app/src/main/java/eu/faircode/email/Helper.java
+++ b/app/src/main/java/eu/faircode/email/Helper.java
@@ -149,10 +149,13 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.LinkedBlockingQueue;
@@ -2224,6 +2227,22 @@ public class Helper {
 
     public static native void sync();
 
+    private static final Map<File, Boolean> exists = new HashMap<>();
+
+    static File ensureExists(File dir) {
+        synchronized (exists) {
+            if (exists.containsKey(dir))
+                return dir;
+            exists.put(dir, true);
+        }
+
+        if (!dir.exists())
+            if (!dir.mkdirs())
+                Log.e("Cannot create directory=" + dir);
+
+        return dir;
+    }
+
     static String sanitizeFilename(String name) {
         if (name == null)
             return null;
diff --git a/app/src/main/java/eu/faircode/email/ImageHelper.java b/app/src/main/java/eu/faircode/email/ImageHelper.java
index 72c3aeeba6..948b93237b 100644
--- a/app/src/main/java/eu/faircode/email/ImageHelper.java
+++ b/app/src/main/java/eu/faircode/email/ImageHelper.java
@@ -804,9 +804,7 @@ class ImageHelper {
 
     @NonNull
     static File getCacheFile(Context context, long id, String source, String extension) {
-        File dir = new File(context.getFilesDir(), "images");
-        if (!dir.exists())
-            dir.mkdir();
+        File dir = Helper.ensureExists(new File(context.getFilesDir(), "images"));
         return new File(dir, id + "_" + Math.abs(source.hashCode()) + extension);
     }