diff --git a/src/Tester.cpp b/src/Tester.cpp
index cd8c8c94fa75..aa680165550f 100644
--- a/src/Tester.cpp
+++ b/src/Tester.cpp
@@ -77,9 +77,8 @@ static void MobiSaveImage(const char* filePathBase, size_t imgNo, ByteSlice img)
     }
     const char* ext = GfxFileExtFromData(img);
     CrashAlwaysIf(!ext);
-    char* path = str::Format("%s_img_%d%s", filePathBase, (int)imgNo, ext);
+    TempStr path = str::FormatTemp("%s_img_%d%s", filePathBase, (int)imgNo, ext);
     file::WriteFile(path, img);
-    str::Free(path);
 }
 
 static void MobiSaveImages(const char* filePathBase, MobiDoc* mb) {
diff --git a/src/Uninstaller.cpp b/src/Uninstaller.cpp
index d2a316613e5a..5bb3549a0a5c 100644
--- a/src/Uninstaller.cpp
+++ b/src/Uninstaller.cpp
@@ -170,7 +170,7 @@ static bool UninstallerOnWmCommand(WPARAM wp) {
 #define kInstallerWindowClassName L"SUMATRA_PDF_INSTALLER_FRAME"
 
 static void CreateUninstallerWindow() {
-    AutoFreeWstr title = str::Format(_TR("SumatraPDF %s Uninstaller"), CURR_VERSION_STR);
+    TempStr title = str::FormatTemp(_TRA("SumatraPDF %s Uninstaller"), CURR_VERSION_STRA);
     int x = CW_USEDEFAULT;
     int y = CW_USEDEFAULT;
     int dx = GetInstallerWinDx();
@@ -178,7 +178,7 @@ static void CreateUninstallerWindow() {
     HMODULE h = GetModuleHandleW(nullptr);
     DWORD dwStyle = WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_CLIPCHILDREN;
     auto winCls = kInstallerWindowClassName;
-    gHwndFrame = CreateWindowW(winCls, title.Get(), dwStyle, x, y, dx, dy, nullptr, nullptr, h, nullptr);
+    gHwndFrame = CreateWindowW(winCls, ToWStrTemp(title), dwStyle, x, y, dx, dy, nullptr, nullptr, h, nullptr);
 
     DpiScale(gHwndFrame, dx, dy);
     HwndResizeClientSize(gHwndFrame, dx, dy);
@@ -189,8 +189,8 @@ static void CreateUninstallerWindow() {
 
 static void ShowUsage() {
     // Note: translation services aren't initialized at this point, so English only
-    char* caption = str::JoinTemp(kAppName, " Uninstaller Usage");
-    AutoFreeStr msg = str::Format(
+    TempStr caption = str::JoinTemp(kAppName, " Uninstaller Usage");
+    TempStr msg = str::FormatTemp(
         "uninstall.exe [/s][/d <path>]\n\
     \n\
     /s\tuninstalls %s silently (without user interaction).\n\
@@ -408,7 +408,7 @@ static void InitSelfDelete() {
         return;
     }
     logf("Created self-delete batch script '%s'\n", scriptPath);
-    AutoFreeStr cmdLine = str::Format("cmd.exe /C \"%s\"", scriptPath);
+    TempStr cmdLine = str::FormatTemp("cmd.exe /C \"%s\"", scriptPath);
     DWORD flags = CREATE_NO_WINDOW;
     LaunchProcess(cmdLine, nullptr, flags);
 }
diff --git a/src/UpdateCheck.cpp b/src/UpdateCheck.cpp
index c002bdf2a89d..140b47124e14 100644
--- a/src/UpdateCheck.cpp
+++ b/src/UpdateCheck.cpp
@@ -479,7 +479,7 @@ void UpdateSelfTo(const char* path) {
     // had time to exit so that we can overwrite it
     ::Sleep(gCli->sleepMs);
 
-    const char* srcPath = GetExePathTemp();
+    TempStr srcPath = GetExePathTemp();
     bool ok = file::Copy(path, srcPath, false);
     // TODO: maybe retry if copy fails under the theory that the file
     // might be temporarily locked
@@ -489,6 +489,6 @@ void UpdateSelfTo(const char* path) {
     }
     logf("UpdateSelfTo: copied self to file\n");
 
-    AutoFreeStr args = str::Format(R"(-sleep-ms 500 -delete-file "%s")", srcPath);
-    CreateProcessHelper(path, args.Get());
+    TempStr args = str::FormatTemp(R"(-sleep-ms 500 -delete-file "%s")", srcPath);
+    CreateProcessHelper(path, args);
 }
diff --git a/src/tools/plugin-test.cpp b/src/tools/plugin-test.cpp
index d806ca3a1a08..22b45576c8cf 100644
--- a/src/tools/plugin-test.cpp
+++ b/src/tools/plugin-test.cpp
@@ -30,9 +30,10 @@ LRESULT CALLBACK PluginParentWndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
     if (WM_CREATE == msg) {
         // run SumatraPDF.exe with the -plugin command line argument
         PluginStartData* data = (PluginStartData*)((CREATESTRUCT*)lp)->lpCreateParams;
-        AutoFreeStr cmdLine(str::Format("-plugin %d \"%s\"", hwnd, data->filePath));
+        auto path = data->filePath;
+        TempStr cmdLine = str::FormatTemp("-plugin %d \"%s\"", hwnd, path);
         if (data->fileOriginUrl) {
-            cmdLine.Set(str::Format("-plugin \"%s\" %d \"%s\"", data->fileOriginUrl, hwnd, data->filePath));
+            cmdLine = str::FormatTemp("-plugin \"%s\" %d \"%s\"", data->fileOriginUrl, hwnd, path);
         }
         ShellExecute(hwnd, L"open", ToWStrTemp(data->sumatraPath), ToWStrTemp(cmdLine), nullptr, SW_SHOW);
     } else if (WM_SIZE == msg) {
diff --git a/src/uia/PageProvider.cpp b/src/uia/PageProvider.cpp
index 9aa73978d9dc..ad3053cf9a5f 100644
--- a/src/uia/PageProvider.cpp
+++ b/src/uia/PageProvider.cpp
@@ -192,7 +192,8 @@ HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::GetPropertyValue(PROP
 
     if (propertyId == UIA_NamePropertyId) {
         pRetVal->vt = VT_BSTR;
-        pRetVal->bstrVal = SysAllocString(AutoFreeWstr(str::Format(L"Page %d", pageNum)));
+        TempStr s = str::FormatTemp("Page %d", pageNum);
+        pRetVal->bstrVal = SysAllocString(ToWStrTemp(s));
         return S_OK;
     } else if (propertyId == UIA_IsValuePatternAvailablePropertyId) {
         pRetVal->vt = VT_BOOL;
diff --git a/src/utils/FileUtil.cpp b/src/utils/FileUtil.cpp
index 9939e94b3bf9..c3ba77893f2d 100644
--- a/src/utils/FileUtil.cpp
+++ b/src/utils/FileUtil.cpp
@@ -710,10 +710,11 @@ int GetZoneIdentifier(const char* filePath) {
 }
 
 bool SetZoneIdentifier(const char* filePath, int zoneId) {
-    char* path = str::JoinTemp(filePath, ":Zone.Identifier");
-    AutoFreeWstr id(str::Format(L"%d", zoneId));
-    WCHAR* pathW = ToWStrTemp(path);
-    return WritePrivateProfileStringW(L"ZoneTransfer", L"ZoneId", id, pathW);
+    TempStr path = str::JoinTemp(filePath, ":Zone.Identifier");
+    TempStr id = str::FormatTemp("%d", zoneId);
+    TempWStr idw = ToWStrTemp(id);
+    TempWStr pathW = ToWStrTemp(path);
+    return WritePrivateProfileStringW(L"ZoneTransfer", L"ZoneId", idw, pathW);
 }
 
 bool DeleteZoneIdentifier(const char* filePath) {