diff --git a/tools/lammps-gui/TODO.md b/tools/lammps-gui/TODO.md
index c54550fbfd..7af492888e 100644
--- a/tools/lammps-gui/TODO.md
+++ b/tools/lammps-gui/TODO.md
@@ -2,8 +2,6 @@ LAMMPS-GUI TODO list:
 
 # Short term goals
 
-- use qgetenv, qputenv for portability
-- use QFile/QDir/QFileInto for portable file and directory operations.
 - write LAMMPS GUI Howto showing/explaining options -> simplify docs and readme
 - rewrite syntax highlighting to be line oriented instead of word oriented.
   handle first part of line based on regular expressions, then advance and only highlight strings and numbers.
diff --git a/tools/lammps-gui/imageviewer.cpp b/tools/lammps-gui/imageviewer.cpp
index 526f9c41d0..bef2589a2a 100644
--- a/tools/lammps-gui/imageviewer.cpp
+++ b/tools/lammps-gui/imageviewer.cpp
@@ -170,7 +170,7 @@ void ImageViewer::createImage()
 {
     QSettings settings;
     QString dumpcmd = QString("write_dump ") + group + " image ";
-    QDir dumpdir    = settings.value("tempdir").toString();
+    QDir dumpdir(QDir::tempPath());
     QFile dumpfile(dumpdir.absoluteFilePath(filename + ".ppm"));
     dumpcmd += dumpfile.fileName();
 
diff --git a/tools/lammps-gui/imageviewer.h b/tools/lammps-gui/imageviewer.h
index 3e038f0231..5319ffc6b2 100644
--- a/tools/lammps-gui/imageviewer.h
+++ b/tools/lammps-gui/imageviewer.h
@@ -55,6 +55,7 @@ private slots:
 
 public:
     void createImage();
+
 private:
     void createActions();
     void updateActions();
diff --git a/tools/lammps-gui/lammpsgui.cpp b/tools/lammps-gui/lammpsgui.cpp
index 5ef4fc8f88..76f1d9f753 100644
--- a/tools/lammps-gui/lammpsgui.cpp
+++ b/tools/lammps-gui/lammpsgui.cpp
@@ -48,12 +48,6 @@
 #include <omp.h>
 #endif
 
-#if defined(_WIN32)
-#include <io.h>
-#else
-#include <unistd.h>
-#endif
-
 static const QString blank(" ");
 static constexpr int MAXRECENT = 5;
 
@@ -114,35 +108,14 @@ LammpsGui::LammpsGui(QWidget *parent, const char *filename) :
 #if defined(_OPENMP)
     // use maximum number of available threads unless OMP_NUM_THREADS was set
     int nthreads = settings.value("nthreads", omp_get_max_threads()).toInt();
-#if _WIN32
-    if (!getenv("OMP_NUM_THREADS")) {
-        _putenv_s("OMP_NUM_THREADS", std::to_string(nthreads).c_str());
+    if (!qEnvironmentVariableIsSet("OMP_NUM_THREADS")) {
+        qputenv("OMP_NUM_THREADS", std::to_string(nthreads).c_str());
     }
-#else
-    setenv("OMP_NUM_THREADS", std::to_string(nthreads).c_str(), 0);
-#endif
 #else
     int nthreads = settings.value("nthreads", 1).toInt();
 #endif
     settings.setValue("nthreads", QString::number(nthreads));
 
-    const char *tmpdir = getenv("TMPDIR");
-    if (!tmpdir) tmpdir = getenv("TMP");
-    if (!tmpdir) tmpdir = getenv("TEMPDIR");
-    if (!tmpdir) tmpdir = getenv("TEMP");
-#if _WIN32
-    if (!tmpdir) tmpdir = "C:\\Windows\\Temp";
-#else
-    if (!tmpdir) tmpdir = "/tmp";
-#endif
-
-    QFileInfo newtmp(settings.value("tempdir", QString(tmpdir)).toString());
-    if (newtmp.isDir() && newtmp.isWritable()) {
-        settings.setValue("tempdir", newtmp.filePath());
-    } else {
-        settings.setValue("tempdir", QString(tmpdir));
-    }
-
     lammps_args.clear();
     lammps_args.push_back(mystrdup("LAMMPS-GUI"));
     lammps_args.push_back(mystrdup("-log"));
@@ -666,12 +639,8 @@ void LammpsGui::run_buffer()
     logwindow->setWindowTitle("LAMMPS-GUI - Output from running LAMMPS on buffer - " +
                               current_file);
     logwindow->setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
-#if (__APPLE__)
-    QFont text_font("Menlo");
-#else
-    QFont text_font(":/Monospace.ttf");
-#endif
-    text_font.setStyleHint(QFont::TypeWriter);
+    QFont text_font;
+    text_font.fromString(settings.value("textfont", text_font.toString()).toString());
     logwindow->document()->setDefaultFont(text_font);
     logwindow->setLineWrapMode(LogWindow::NoWrap);
     logwindow->setMinimumSize(400, 300);
diff --git a/tools/lammps-gui/preferences.cpp b/tools/lammps-gui/preferences.cpp
index fb83a8b3f9..0cd8b19a3a 100644
--- a/tools/lammps-gui/preferences.cpp
+++ b/tools/lammps-gui/preferences.cpp
@@ -99,11 +99,6 @@ void Preferences::accept()
     if (field)
         if (field->hasAcceptableInput()) settings->setValue("nthreads", field->text());
 
-    // store temp dir
-    field = tabWidget->findChild<QLineEdit *>("tmpedit");
-    if (field)
-        if (field->hasAcceptableInput()) settings->setValue("tempdir", field->text());
-
     // store image width, height, zoom, and rendering settings
 
     settings->beginGroup("snapshot");
@@ -173,17 +168,6 @@ GeneralTab::GeneralTab(QSettings *_settings, LammpsWrapper *_lammps, QWidget *pa
     pltr->setObjectName("chartreplace");
     pltr->setCheckState(settings->value("chartreplace", false).toBool() ? Qt::Checked
                                                                         : Qt::Unchecked);
-#if !defined(__APPLE__)
-    auto *tmplabel  = new QLabel("Scratch Folder:");
-    auto *tmpedit   = new QLineEdit(settings->value("tempdir", ".").toString());
-    auto *tmpbrowse = new QPushButton("Browse...");
-    auto *tmplayout = new QHBoxLayout;
-    tmpedit->setObjectName("tmpedit");
-    tmplayout->addWidget(tmplabel);
-    tmplayout->addWidget(tmpedit);
-    tmplayout->addWidget(tmpbrowse);
-    connect(tmpbrowse, &QPushButton::released, this, &GeneralTab::newtmpfolder);
-#endif
 
 #if defined(LAMMPS_GUI_USE_PLUGIN)
     auto *pluginlabel = new QLabel("Path to LAMMPS Shared Library File:");
@@ -213,9 +197,6 @@ GeneralTab::GeneralTab(QSettings *_settings, LammpsWrapper *_lammps, QWidget *pa
     layout->addWidget(logr);
     layout->addWidget(pltr);
     layout->addWidget(imgr);
-#if !defined(__APPLE__)
-    layout->addLayout(tmplayout);
-#endif
 #if defined(LAMMPS_GUI_USE_PLUGIN)
     layout->addWidget(pluginlabel);
     layout->addLayout(pluginlayout);
@@ -263,18 +244,6 @@ void GeneralTab::newtextfont()
     settings.setValue("textfont", font.toString());
 }
 
-void GeneralTab::newtmpfolder()
-{
-    QLineEdit *field = findChild<QLineEdit *>("tmpedit");
-    QString tmpdir =
-        QFileDialog::getExistingDirectory(this, "Find Folder for Temporary Files", field->text());
-
-    if (!tmpdir.isEmpty()) {
-        QFileInfo newtmp(tmpdir);
-        if (newtmp.isDir() && newtmp.isWritable()) field->setText(tmpdir);
-    }
-}
-
 void GeneralTab::pluginpath()
 {
     QLineEdit *field = findChild<QLineEdit *>("pluginedit");
diff --git a/tools/lammps-gui/preferences.h b/tools/lammps-gui/preferences.h
index fe487c8a7f..b5529b0c46 100644
--- a/tools/lammps-gui/preferences.h
+++ b/tools/lammps-gui/preferences.h
@@ -49,7 +49,6 @@ public:
 
 private slots:
     void pluginpath();
-    void newtmpfolder();
     void newallfont();
     void newtextfont();