diff --git a/core/PaymentReceiptProcess.cs b/core/PaymentReceiptProcess.cs
index a9d746e..fc5896f 100644
--- a/core/PaymentReceiptProcess.cs
+++ b/core/PaymentReceiptProcess.cs
@@ -18,6 +18,7 @@ namespace dezentrale.core
     public interface IPaymentReceiptProcessData
     {
         List<Member> MemberList         { get; set; }
+        bool AllMembers                 { get; set; }
         string DataTemplate             { get; set; }
         IntermediateFormat DataFormat   { get; set; }
 
@@ -28,6 +29,7 @@ namespace dezentrale.core
         string StartDateString          { get; }
         string EndDateString            { get; }
         bool SendEmail                  { get; set; }
+        bool WriteProtectPdf            { get; set; }
     }
 
     //In order to be able to ReplaceReflect, we need to have the SvgData and SvgFileName field separated in a class
@@ -58,7 +60,7 @@ namespace dezentrale.core
             this.data = data;
 
             Caption = "Generate receipt PDF for each membership payment";
-            Steps = 5;
+            Steps = 6;
         }
 
         //! \short  Run receipt generation process
@@ -70,7 +72,21 @@ namespace dezentrale.core
             uint step = 0;
             try
             {
-                List<Member> memberList = data.MemberList ?? Program.members.Entries;
+                List<Member> memberList;
+                bool allMembers = data.AllMembers;
+                if (data.MemberList == null || data.MemberList.Count < 1)
+                {
+                    if(!data.AllMembers)
+                    {
+                        LogTarget.LogLine($"No member list provided", LogEvent.ELogLevel.Error, "PaymentReceiptProcess");
+                        return false;
+                    }
+                    memberList = Program.members.Entries;
+                } else
+                {
+                    memberList = allMembers ? Program.members.Entries : data.MemberList;
+                    LogTarget.LogLine($"Processing {memberList.Count} entries (AllMembers={allMembers})", LogEvent.ELogLevel.Error, "PaymentReceiptProcess");
+                }
 
                 // In preparation to send E-Mail and combine multiple files into one mail later,
                 // we're using a List of KVP with key = filename, value = member reference
@@ -107,7 +123,10 @@ namespace dezentrale.core
                     Member m = memberList.Find(x => x.Number == mt.MemberNumber);
                     if(m == null)
                     {
-                        LogTarget.LogLine($"Cannot find member {mt.MemberNumber} referenced in MoneyTransfer {mt.Id} (from {mt.ValutaDate})", LogEvent.ELogLevel.Error, "PaymentReceiptProcess");
+                        //this is only an error, if all members are selected in the dialog, we can check this.
+                        if(allMembers)
+                            LogTarget.LogLine($"Cannot find member {mt.MemberNumber} referenced in MoneyTransfer {mt.Id} (from {mt.ValutaDate})", LogEvent.ELogLevel.Error, "PaymentReceiptProcess");
+                        //but in every case, we need to skip this MoneyTransfer.
                         continue;
                     }
                     if(!m.MoneyTransfersIds.Contains(mt.Id))
@@ -141,8 +160,14 @@ namespace dezentrale.core
                             ImportExportBase.RunProcess("pdflatex", $"\"{sourceFile}\"", ".", LogTarget);
                             break;
                     }
-                }
 
+                    if(data.WriteProtectPdf && data.DataFormat != IntermediateFormat.Text)
+                    {
+                        //Write-protecting pdf
+                        ImportExportBase.RunProcess("qpdf", $"--encrypt \"\" \"random-owner-pw\" 256 --modify=none -- \"{pdf}\" \"{pdf}.writeprotect\"", ".", LogTarget);
+                        File.Replace(pdf, pdf + ".writeprotect", pdf + ".writable");
+                    }
+                }
 
                 LogTarget.StepStarted(++step, "E-Mail the PDFs to the members");
                 if (data.SendEmail)
diff --git a/view/frmMain.cs b/view/frmMain.cs
index 1ad65ac..9a9453a 100644
--- a/view/frmMain.cs
+++ b/view/frmMain.cs
@@ -121,9 +121,10 @@ namespace dezentrale.view
             int totalHours = (int) now.Subtract(Program.config.LastDbImport).TotalHours;
             int totalDays = totalHours / 24;
             if (totalHours >= 8)
-            {
+            {
+                totalHours %= 24;
                 string timeSpan = $"{totalDays} d, {totalHours} h";
-                totalHours %= 24;
+
                 if (Program.config.DbChangedSinceExport)
                 {
                     MessageBox.Show(    "Warning: There are local changes to DB since last export!\r\n"
diff --git a/view/frmPaymentReceipts.cs b/view/frmPaymentReceipts.cs
index 32ff8cb..75be6f0 100644
--- a/view/frmPaymentReceipts.cs
+++ b/view/frmPaymentReceipts.cs
@@ -32,6 +32,7 @@ namespace dezentrale.view
     public class frmPaymentReceipts : FormWithOkCancel, IPaymentReceiptProcessData
     {
         public List<Member> MemberList       { get; set; } = null;
+        public bool AllMembers               { get; set; } = false;
         public string DataTemplate           { get; set; } = "";
         public IntermediateFormat DataFormat { get; set; } = IntermediateFormat.Text;
         public string OutputDirectory        { get; set; } = "";
@@ -41,6 +42,7 @@ namespace dezentrale.view
         public bool SendEmail                { get; set; } = false;
         public string StartDateString        { get { return StartDate.ToShortDateString(); } }
         public string EndDateString          { get { return EndDate  .ToShortDateString(); } }
+        public bool WriteProtectPdf          { get; set; } = false;
 
         private TextBox tbTemplate;
         private ComboBox cbDataFormat;
@@ -51,13 +53,14 @@ namespace dezentrale.view
         private RadioButton optAllMembers;
         private RadioButton optSelectedMembers;
         private CheckBox chkSendEmail;
+        private CheckBox chkWriteProtectPdf;
 
         public frmPaymentReceipts()
         {
             DialogResult = DialogResult.Cancel;
             this.StartPosition = FormStartPosition.CenterParent;
-            this.Size        = new System.Drawing.Size(483, 310);
-            this.MinimumSize = new System.Drawing.Size(455, 310);
+            this.Size        = new System.Drawing.Size(483, 320);
+            this.MinimumSize = new System.Drawing.Size(455, 320);
             this.Text = "Generate payment receipts";
             this.Controls.Add(new Label()
                 {
@@ -98,6 +101,10 @@ namespace dezentrale.view
                 });
             foreach (IntermediateFormat fmt in Enum.GetValues(typeof(IntermediateFormat)))
                 cbDataFormat.Items.Add(fmt);
+            cbDataFormat.SelectedValueChanged += (sender, e) =>
+                {
+                    chkWriteProtectPdf.Enabled = (IntermediateFormat)cbDataFormat.SelectedItem != IntermediateFormat.Text;
+                };
 
             this.Controls.Add(new Label()
                 {
@@ -201,6 +208,12 @@ namespace dezentrale.view
                     Width = 300,
                     Location = new Point(lm + 113, 8 * line + tm),
                 });
+            this.Controls.Add(chkWriteProtectPdf = new CheckBox()
+                {
+                    Text = "Ausgabe schreibschützen (QPDF erforderlich)",
+                    Width = 300,
+                    Location = new Point(lm + 113, 9 * line + tm),
+                });
 
             AddOkCancel(this, btnOK_Click, btnCancel_Click);
 
@@ -215,13 +228,17 @@ namespace dezentrale.view
                 dtStartDate.Value = StartDate;
                 dtEndDate.Value = EndDate;
                 if (MemberList != null && MemberList.Count > 0)
-                    optSelectedMembers.Checked = true;
+                {
+                    optAllMembers.Checked      = AllMembers;
+                    optSelectedMembers.Checked = !AllMembers;
+                }
                 else
                 {
                     optAllMembers.Checked = true;
                     optSelectedMembers.Enabled = false;
                 }
                 chkSendEmail.Checked = SendEmail;
+                chkWriteProtectPdf.Checked = WriteProtectPdf;
             };
         }
 
@@ -263,6 +280,7 @@ namespace dezentrale.view
 
         private void btnOK_Click(object sender, EventArgs e)
         {
+            AllMembers = optAllMembers.Checked;
             DataTemplate = tbTemplate.Text;
             DataFormat = (IntermediateFormat) cbDataFormat.SelectedItem;
             OutputDirectory = tbOutputDirectory.Text;
@@ -271,6 +289,7 @@ namespace dezentrale.view
             EndDate = dtEndDate.Value.AddSeconds(24*60*60 - 1);
             if (optSelectedMembers.Checked != true) MemberList = null;
             SendEmail = chkSendEmail.Checked;
+            WriteProtectPdf = chkWriteProtectPdf.Checked;
             DialogResult = DialogResult.OK;
             this.Close();
         }