diff --git a/dll/win32/kernel32/wine/profile.c b/dll/win32/kernel32/wine/profile.c
index f89da3f2988..58282e78492 100644
--- a/dll/win32/kernel32/wine/profile.c
+++ b/dll/win32/kernel32/wine/profile.c
@@ -1210,7 +1210,7 @@ INT WINAPI GetPrivateProfileStringA( LPCSTR section, LPCSTR entry,
     LPWSTR bufferW;
     INT retW, ret = 0;
 
-    bufferW = buffer ? HeapAlloc(GetProcessHeap(), 0, len * sizeof(WCHAR)) : NULL;
+    bufferW = buffer ? HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, len * sizeof(WCHAR)) : NULL;
     if (section) RtlCreateUnicodeStringFromAsciiz(&sectionW, section);
     else sectionW.Buffer = NULL;
     if (entry) RtlCreateUnicodeStringFromAsciiz(&entryW, entry);
@@ -1227,10 +1227,21 @@ INT WINAPI GetPrivateProfileStringA( LPCSTR section, LPCSTR entry,
     {
         if (retW)
         {
+            if (retW < (INT)len - 1)
+            {
+                /* also convert the final string terminator */
+                if (!entryW.Buffer && retW < (INT)len - 2)
+                    retW++; /* section enumeration: also convert the list terminator */
+                retW++;
+            }
             ret = WideCharToMultiByte(CP_ACP, 0, bufferW, retW, buffer, len - 1, NULL, NULL);
-            if (!ret)
-                ret = len - 1;
+            if (ret == len - 1)  /* overflow */
+            {
+                ret = len - 2;
+                buffer[ret] = 0;
+            }
         }
+        /* buffer stays double-nul terminated: it was zero-initialized */
         buffer[ret] = 0;
     }
 
@@ -1392,15 +1403,15 @@ INT WINAPI GetPrivateProfileSectionA( LPCSTR section, LPSTR buffer,
         return 0;
     }
 
-    bufferW = HeapAlloc(GetProcessHeap(), 0, len * 2 * sizeof(WCHAR));
+    bufferW = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, len * 2 * sizeof(WCHAR));
     RtlCreateUnicodeStringFromAsciiz(&sectionW, section);
     if (filename) RtlCreateUnicodeStringFromAsciiz(&filenameW, filename);
     else filenameW.Buffer = NULL;
 
     retW = GetPrivateProfileSectionW(sectionW.Buffer, bufferW, len * 2, filenameW.Buffer);
+    if (retW == len * 2 - 2) retW++;  /* overflow */
     if (retW)
     {
-        if (retW == len * 2 - 2) retW++;  /* overflow */
         ret = WideCharToMultiByte(CP_ACP, 0, bufferW, retW + 1, buffer, len, NULL, NULL);
         if (!ret || ret == len)  /* overflow */
         {
diff --git a/win32ss/printing/base/winspool/printers.c b/win32ss/printing/base/winspool/printers.c
index 2f874c81e05..caea5f596ec 100644
--- a/win32ss/printing/base/winspool/printers.c
+++ b/win32ss/printing/base/winspool/printers.c
@@ -196,27 +196,40 @@ Cleanup:
     return (dwErrorCode == ERROR_SUCCESS);
 }
 
+static PWSTR
+AsciiStringToUnicode(LPCSTR pstr)
+{
+    UNICODE_STRING us;
+    PWSTR pwsz = NULL;
+
+    if (pstr)
+    {
+        RtlCreateUnicodeStringFromAsciiz(&us, pstr);
+        pwsz = us.Buffer;
+    }
+    return pwsz;
+}
+
+static VOID
+FreeUnicodeString(PWSTR pwsz)
+{
+    UNICODE_STRING us;
+
+    if (pwsz)
+    {
+        us.Buffer = pwsz;
+        RtlFreeUnicodeString(&us);
+    }
+}
+
 HANDLE WINAPI
 AddPrinterA(PSTR pName, DWORD Level, PBYTE pPrinter)
 {
-    UNICODE_STRING pNameW, usBuffer;
+    UNICODE_STRING usNameW;
     PWSTR pwstrNameW;
-    PRINTER_INFO_2W *ppi2w = (PRINTER_INFO_2W*)pPrinter;
     PRINTER_INFO_2A *ppi2a = (PRINTER_INFO_2A*)pPrinter;
+    PRINTER_INFO_2W pi2w;
     HANDLE ret = NULL;
-    PWSTR pwszPrinterName = NULL;
-    PWSTR pwszServerName = NULL;
-    PWSTR pwszShareName = NULL;
-    PWSTR pwszPortName = NULL;
-    PWSTR pwszDriverName = NULL;
-    PWSTR pwszComment = NULL;
-    PWSTR pwszLocation = NULL;
-    PWSTR pwszSepFile = NULL;
-    PWSTR pwszPrintProcessor = NULL;
-    PWSTR pwszDatatype = NULL;
-    PWSTR pwszParameters = NULL;
-    PWSTR pPrintProcessor = NULL;
-    PDEVMODEW pdmw = NULL;
 
     TRACE("AddPrinterA(%s, %d, %p)\n", debugstr_a(pName), Level, pPrinter);
 
@@ -227,91 +240,103 @@ AddPrinterA(PSTR pName, DWORD Level, PBYTE pPrinter)
         return NULL;
     }
 
-    pwstrNameW = AsciiToUnicode(&pNameW,pName);
+    pwstrNameW = AsciiToUnicode(&usNameW, pName);
 
+    /* Do NOT overwrite the caller's ANSI structure in place.
+     * Use a temporary Unicode PRINTER_INFO_2W on the stack and convert
+     * each ANSI string field to its Unicode counterpart. */
+    ZeroMemory(&pi2w, sizeof(pi2w));
+
+    if (ppi2a->pServerName)
+    {
+        pi2w.pServerName = AsciiStringToUnicode(ppi2a->pServerName);
+        if (!pi2w.pServerName) goto Cleanup;
+    }
+    if (ppi2a->pPrinterName)
+    {
+        pi2w.pPrinterName = AsciiStringToUnicode(ppi2a->pPrinterName);
+        if (!pi2w.pPrinterName) goto Cleanup;
+    }
     if (ppi2a->pShareName)
     {
-        pwszShareName = AsciiToUnicode(&usBuffer, ppi2a->pShareName);
-        if (!(ppi2w->pShareName = pwszShareName)) goto Cleanup;
+        pi2w.pShareName = AsciiStringToUnicode(ppi2a->pShareName);
+        if (!pi2w.pShareName) goto Cleanup;
     }
     if (ppi2a->pPortName)
     {
-        pwszPortName = AsciiToUnicode(&usBuffer, ppi2a->pPortName);
-        if (!(ppi2w->pPortName = pwszPortName)) goto Cleanup;
+        pi2w.pPortName = AsciiStringToUnicode(ppi2a->pPortName);
+        if (!pi2w.pPortName) goto Cleanup;
     }
     if (ppi2a->pDriverName)
     {
-        pwszDriverName = AsciiToUnicode(&usBuffer, ppi2a->pDriverName);
-        if (!(ppi2w->pDriverName = pwszDriverName)) goto Cleanup;
+        pi2w.pDriverName = AsciiStringToUnicode(ppi2a->pDriverName);
+        if (!pi2w.pDriverName) goto Cleanup;
     }
     if (ppi2a->pComment)
     {
-        pwszComment = AsciiToUnicode(&usBuffer, ppi2a->pComment);
-        if (!(ppi2w->pComment = pwszComment)) goto Cleanup;
+        pi2w.pComment = AsciiStringToUnicode(ppi2a->pComment);
+        if (!pi2w.pComment) goto Cleanup;
     }
     if (ppi2a->pLocation)
     {
-        pwszLocation = AsciiToUnicode(&usBuffer, ppi2a->pLocation);
-        if (!(ppi2w->pLocation = pwszLocation)) goto Cleanup;
+        pi2w.pLocation = AsciiStringToUnicode(ppi2a->pLocation);
+        if (!pi2w.pLocation) goto Cleanup;
+    }
+    if (ppi2a->pDevMode)
+    {
+        RosConvertAnsiDevModeToUnicodeDevmode(ppi2a->pDevMode, &pi2w.pDevMode);
+        if (!pi2w.pDevMode) goto Cleanup;
     }
     if (ppi2a->pSepFile)
     {
-        pwszSepFile = AsciiToUnicode(&usBuffer, ppi2a->pSepFile);
-        if (!(ppi2w->pSepFile = pwszSepFile)) goto Cleanup;
+        pi2w.pSepFile = AsciiStringToUnicode(ppi2a->pSepFile);
+        if (!pi2w.pSepFile) goto Cleanup;
     }
-    if (ppi2a->pServerName)
+    if (ppi2a->pPrintProcessor)
     {
-        pwszPrintProcessor = AsciiToUnicode(&usBuffer, ppi2a->pPrintProcessor);
-        if (!(ppi2w->pPrintProcessor = pwszPrintProcessor)) goto Cleanup;
+        pi2w.pPrintProcessor = AsciiStringToUnicode(ppi2a->pPrintProcessor);
+        if (!pi2w.pPrintProcessor) goto Cleanup;
     }
     if (ppi2a->pDatatype)
     {
-        pwszDatatype = AsciiToUnicode(&usBuffer, ppi2a->pDatatype);
-        if (!(ppi2w->pDatatype = pwszDatatype)) goto Cleanup;
+        pi2w.pDatatype = AsciiStringToUnicode(ppi2a->pDatatype);
+        if (!pi2w.pDatatype) goto Cleanup;
     }
     if (ppi2a->pParameters)
     {
-        pwszParameters = AsciiToUnicode(&usBuffer, ppi2a->pParameters);
-        if (!(ppi2w->pParameters = pwszParameters)) goto Cleanup;
-    }
-    if ( ppi2a->pDevMode )
-    {
-        RosConvertAnsiDevModeToUnicodeDevmode( ppi2a->pDevMode, &pdmw );
-        ppi2w->pDevMode = pdmw;
-    }
-    if (ppi2a->pServerName)
-    {
-        pwszServerName = AsciiToUnicode(&usBuffer, ppi2a->pServerName);
-        if (!(ppi2w->pPrinterName = pwszServerName)) goto Cleanup;
-    }
-    if (ppi2a->pPrinterName)
-    {
-        pwszPrinterName = AsciiToUnicode(&usBuffer, ppi2a->pPrinterName);
-        if (!(ppi2w->pPrinterName = pwszPrinterName)) goto Cleanup;
-    }
-    if (ppi2a->pPrintProcessor)
-    {
-        pPrintProcessor = AsciiToUnicode(&usBuffer, ppi2a->pPrintProcessor);
-        if (!(ppi2w->pPrintProcessor = pPrintProcessor)) goto Cleanup;
+        pi2w.pParameters = AsciiStringToUnicode(ppi2a->pParameters);
+        if (!pi2w.pParameters) goto Cleanup;
     }
 
-    ret = AddPrinterW(pwstrNameW, Level, (LPBYTE)ppi2w);
+    /* Copy scalar fields. */
+    pi2w.pSecurityDescriptor = ppi2a->pSecurityDescriptor;
+    pi2w.Attributes = ppi2a->Attributes;
+    pi2w.Priority = ppi2a->Priority;
+    pi2w.DefaultPriority = ppi2a->DefaultPriority;
+    pi2w.StartTime = ppi2a->StartTime;
+    pi2w.UntilTime = ppi2a->UntilTime;
+    pi2w.Status = ppi2a->Status;
+    pi2w.cJobs = ppi2a->cJobs;
+    pi2w.AveragePPM = ppi2a->AveragePPM;
 
-Cleanup:
-    if (pdmw) HeapFree(hProcessHeap, 0, pdmw);
-    if (pwszPrinterName) HeapFree(hProcessHeap, 0, pwszPrinterName);
-    if (pwszServerName) HeapFree(hProcessHeap, 0, pwszServerName);
-    if (pwszShareName) HeapFree(hProcessHeap, 0, pwszShareName);
-    if (pwszPortName) HeapFree(hProcessHeap, 0, pwszPortName);
-    if (pwszDriverName) HeapFree(hProcessHeap, 0, pwszDriverName);
-    if (pwszComment) HeapFree(hProcessHeap, 0, pwszComment);
-    if (pwszLocation) HeapFree(hProcessHeap, 0, pwszLocation);
-    if (pwszSepFile) HeapFree(hProcessHeap, 0, pwszSepFile);
-    if (pwszPrintProcessor) HeapFree(hProcessHeap, 0, pwszPrintProcessor);
-    if (pwszDatatype) HeapFree(hProcessHeap, 0, pwszDatatype);
-    if (pwszParameters) HeapFree(hProcessHeap, 0, pwszParameters);
+    ret = AddPrinterW(pwstrNameW, Level, (LPBYTE)&pi2w);
 
-    RtlFreeUnicodeString(&pNameW);
+Cleanup:
+    /* Free the temporary Unicode strings. */
+    FreeUnicodeString(pi2w.pServerName);
+    FreeUnicodeString(pi2w.pPrinterName);
+    FreeUnicodeString(pi2w.pShareName);
+    FreeUnicodeString(pi2w.pPortName);
+    FreeUnicodeString(pi2w.pDriverName);
+    FreeUnicodeString(pi2w.pComment);
+    FreeUnicodeString(pi2w.pLocation);
+    FreeUnicodeString(pi2w.pSepFile);
+    FreeUnicodeString(pi2w.pPrintProcessor);
+    FreeUnicodeString(pi2w.pDatatype);
+    FreeUnicodeString(pi2w.pParameters);
+    if (pi2w.pDevMode) HeapFree(GetProcessHeap(), 0, pi2w.pDevMode);
+
+    RtlFreeUnicodeString(&usNameW);
     return ret;
 }
 
@@ -3139,6 +3164,9 @@ SetDefaultPrinterW(LPCWSTR pszPrinter)
         goto Cleanup;
     }
 
+    // Keep the legacy win.ini entry in sync.
+    WriteProfileStringW(L"windows", wszDeviceValue, pwszDeviceValueData);
+
 Cleanup:
     if (hDevicesKey)
         RegCloseKey(hDevicesKey);
diff --git a/win32ss/printing/providers/localspl/printers.c b/win32ss/printing/providers/localspl/printers.c
index aaa313d5a4c..9d16fd90d9a 100644
--- a/win32ss/printing/providers/localspl/printers.c
+++ b/win32ss/printing/providers/localspl/printers.c
@@ -1999,6 +1999,67 @@ LocalClosePrinter(HANDLE hPrinter)
     return TRUE;
 }
 
+static
+PWSTR
+BuildDeviceEntryValue(PCWSTR pwszDriverName, PCWSTR pwszPortName, BOOL bWithTimeouts)
+{
+    SIZE_T cchNeeded;
+    PWSTR pwszValue;
+
+    // Build a value of the format "<Driver>,<Port>[,15,45]".
+    cchNeeded = wcslen(pwszDriverName) + 1 + wcslen(pwszPortName) + 1;
+    if (bWithTimeouts)
+        cchNeeded += 6;
+
+    pwszValue = DllAllocSplMem(cchNeeded * sizeof(WCHAR));
+    if (!pwszValue)
+        return NULL;
+
+    wcscpy(pwszValue, pwszDriverName);
+    wcscat(pwszValue, L",");
+    wcscat(pwszValue, pwszPortName);
+
+    if (bWithTimeouts)
+        wcscat(pwszValue, L",15,45");
+
+    return pwszValue;
+}
+
+static
+VOID
+MaintainWinIniEntries(PCWSTR pwszPrinterName, PCWSTR pwszDriverName, PCWSTR pwszPortName)
+{
+    PWSTR pwszValue;
+
+    if (!pwszPrinterName || !*pwszPrinterName)
+        return;
+
+    // Passing NULL as the value deletes the entry.
+    if (!pwszDriverName || !*pwszDriverName || !pwszPortName || !*pwszPortName)
+    {
+        WriteProfileStringW(L"devices", pwszPrinterName, NULL);
+        WriteProfileStringW(L"PrinterPorts", pwszPrinterName, NULL);
+        return;
+    }
+
+    // Maintain the legacy win.ini sections [devices] and [PrinterPorts] like the
+    // Windows NT print spooler does, so that applications which enumerate printers
+    // through them (e.g. Visual Basic 6 programs using their Printers collection) work.
+    pwszValue = BuildDeviceEntryValue(pwszDriverName, pwszPortName, FALSE);
+    if (pwszValue)
+    {
+        WriteProfileStringW(L"devices", pwszPrinterName, pwszValue);
+        DllFreeSplMem(pwszValue);
+    }
+
+    pwszValue = BuildDeviceEntryValue(pwszDriverName, pwszPortName, TRUE);
+    if (pwszValue)
+    {
+        WriteProfileStringW(L"PrinterPorts", pwszPrinterName, pwszValue);
+        DllFreeSplMem(pwszValue);
+    }
+}
+
 HANDLE WINAPI
 LocalAddPrinter(LPWSTR pName, DWORD level, LPBYTE pPrinterInfo)
 {
@@ -2204,6 +2265,10 @@ LocalAddPrinter(LPWSTR pName, DWORD level, LPBYTE pPrinterInfo)
 
     // The Printer was added successfully.
     RegCloseKey(hPrinterKey);
+
+    // Keep the legacy win.ini entries in sync.
+    MaintainWinIniEntries(pInfo->pPrinterName, pLocalPrinter->pwszPrinterDriver, pPort->pwszName);
+
     SetLastError(ROUTER_SUCCESS);
     return hPrinter;
 
@@ -2274,6 +2339,9 @@ LocalDeletePrinter(HANDLE hPrinter)
     // Delete the Printer's registry key.
     RegDeleteKeyW(hPrintersKey, pPrinter->pwszPrinterName);
 
+    // Keep the legacy win.ini entries in sync.
+    MaintainWinIniEntries(pPrinter->pwszPrinterName, NULL, NULL);
+
     // Free all resources of the Printer.
     DllFreeSplStr(pPrinter->pwszPrinterName);
     DllFreeSplStr(pPrinter->pwszLocation);