diff --git a/src/common/io/io.h b/src/common/io/io.h
index 8787f9858..d9c24c351 100644
--- a/src/common/io/io.h
+++ b/src/common/io/io.h
@@ -254,4 +254,5 @@ bool ffRemoveFile(const char* fileName);
 #ifdef _WIN32
 // Only O_RDONLY is supported
 HANDLE openat(HANDLE dfd, const char* fileName, bool directory);
+HANDLE openatW(HANDLE dfd, const wchar_t* fileName, uint16_t fileNameLen, bool directory);
 #endif
diff --git a/src/common/io/io_windows.c b/src/common/io/io_windows.c
index ae1d584e9..8724d0ee9 100644
--- a/src/common/io/io_windows.c
+++ b/src/common/io/io_windows.c
@@ -3,8 +3,8 @@
 #include "util/stringUtils.h"
 
 #include <windows.h>
+#include "util/windows/nt.h"
 #include <ntstatus.h>
-#include <winternl.h>
 
 static void createSubfolders(const char* fileName)
 {
@@ -102,31 +102,48 @@ bool ffAppendFileBuffer(const char* fileName, FFstrbuf* buffer)
     return ffAppendFDBuffer(handle, buffer);
 }
 
-HANDLE openat(HANDLE dfd, const char* fileName, bool directory)
+HANDLE openatW(HANDLE dfd, const wchar_t* fileName, uint16_t fileNameLen, bool directory)
 {
-    NTSTATUS ret;
-    UNICODE_STRING fileNameW;
-    ret = RtlAnsiStringToUnicodeString(&fileNameW, &(ANSI_STRING) {
-        .Length = (USHORT) strlen(fileName),
-        .Buffer = (PCHAR) fileName
-    }, TRUE);
-    if (!NT_SUCCESS(ret)) return INVALID_HANDLE_VALUE;
+    assert(fileNameLen <= 0x7FFF);
 
-    FF_AUTO_CLOSE_FD HANDLE hFile;
+    HANDLE hFile;
     IO_STATUS_BLOCK iosb = {};
-    ret = NtOpenFile(&hFile, FILE_READ_DATA | SYNCHRONIZE, &(OBJECT_ATTRIBUTES) {
-        .Length = sizeof(OBJECT_ATTRIBUTES),
-        .RootDirectory = dfd,
-        .ObjectName = &fileNameW,
-    }, &iosb, FILE_SHARE_READ, FILE_SYNCHRONOUS_IO_NONALERT | (directory ? FILE_DIRECTORY_FILE : FILE_NON_DIRECTORY_FILE));
-    RtlFreeUnicodeString(&fileNameW);
-
-    if(!NT_SUCCESS(ret) || iosb.Information != FILE_OPENED)
+    if(!NT_SUCCESS(NtOpenFile(&hFile,
+        (directory ? FILE_LIST_DIRECTORY | FILE_TRAVERSE : FILE_READ_DATA | FILE_READ_EA) | FILE_READ_ATTRIBUTES | SYNCHRONIZE, &(OBJECT_ATTRIBUTES) {
+            .Length = sizeof(OBJECT_ATTRIBUTES),
+            .RootDirectory = dfd,
+            .ObjectName = &(UNICODE_STRING) {
+                .Buffer = (PWSTR) fileName,
+                .Length = fileNameLen * (USHORT) sizeof(wchar_t),
+                .MaximumLength = (fileNameLen + 1) * (USHORT) sizeof(wchar_t),
+            },
+            .Attributes = OBJ_CASE_INSENSITIVE,
+        },
+        &iosb,
+        FILE_SHARE_READ | (directory ? FILE_SHARE_WRITE | FILE_SHARE_DELETE : 0),
+        FILE_SYNCHRONOUS_IO_NONALERT | (directory ? FILE_DIRECTORY_FILE : FILE_NON_DIRECTORY_FILE)
+    )))
         return INVALID_HANDLE_VALUE;
 
     return hFile;
 }
 
+HANDLE openat(HANDLE dfd, const char* fileName, bool directory)
+{
+    wchar_t fileNameW[MAX_PATH];
+    int len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, fileName, -1, fileNameW, ARRAY_SIZE(fileNameW));
+    if (len == 0) return INVALID_HANDLE_VALUE;
+    fileNameW[len] = L'\0';
+
+    for (int i = 0; i < len - 1; ++i)
+    {
+        if (fileNameW[i] == L'/')
+            fileNameW[i] = L'\\';
+    }
+
+    return openatW(dfd, fileNameW, (uint16_t)(len - 1), directory);
+}
+
 bool ffAppendFileBufferRelative(HANDLE dfd, const char* fileName, FFstrbuf* buffer)
 {
     HANDLE FF_AUTO_CLOSE_FD fd = openat(dfd, fileName, false);