diff --git a/src/ksanewidget.cpp b/src/ksanewidget.cpp
--- a/src/ksanewidget.cpp
+++ b/src/ksanewidget.cpp
@@ -712,6 +712,11 @@
     int i;
     int ret = 0;
 
+    if (d->m_previewThread->isRunning() || d->m_scanThread->isRunning()) {
+        d->m_settingsChangePending.reset(new QMap<QString, QString>(opts));
+        return ret;
+    }
+
     for (i = 0; i < d->m_optList.size(); i++) {
         if (opts.contains(d->m_optList.at(i)->name())) {
             tmp = opts[d->m_optList.at(i)->name()];
@@ -758,6 +763,13 @@
 {
     KSaneOption *opt;
 
+    if (d->m_previewThread->isRunning() || d->m_scanThread->isRunning()) {
+        QMap<QString, QString>* opts_copy = new QMap<QString, QString>();
+        (*opts_copy)[option] = value;
+        d->m_settingsChangePending.reset(opts_copy);
+        return false;
+    }
+
     if ((opt = d->getOption(option)) != nullptr) {
         if (opt->setValue(value)) {
             if ((d->m_splitGamChB) &&
diff --git a/src/ksanewidget_p.h b/src/ksanewidget_p.h
--- a/src/ksanewidget_p.h
+++ b/src/ksanewidget_p.h
@@ -43,6 +43,7 @@
 #include <QProgressBar>
 #include <QTabWidget>
 #include <QPushButton>
+#include <QScopedPointer>
 
 #include "ksanewidget.h"
 #include "ksaneoption.h"
@@ -181,6 +182,7 @@
     QTimer              m_optionPollTmr;
     KSaneScanThread    *m_scanThread;
     KSanePreviewThread *m_previewThread;
+    QScopedPointer<QMap<QString, QString> > m_settingsChangePending;
 
     QString             m_saneUserName;
     QString             m_sanePassword;
diff --git a/src/ksanewidget_p.cpp b/src/ksanewidget_p.cpp
--- a/src/ksanewidget_p.cpp
+++ b/src/ksanewidget_p.cpp
@@ -1076,6 +1076,10 @@
             m_optionPollTmr.start();
         }
         emit(q->scanProgress(100));
+
+        if (m_settingsChangePending) {
+            q->setOptVals(*m_settingsChangePending.take());
+        }
     }
 
     m_optsTabWidget->setDisabled(busy);