diff --git a/src/fileio.cpp b/src/fileio.cpp
index da64e5b7f7..ba3abb21a1 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -206,10 +206,10 @@ FILE *FioFOpenFile(const char *filename)
 	FILE *f;
 	char buf[MAX_PATH];
 
-	if (strrchr(filename, PATHSEPCHAR) == NULL) {
-		snprintf(buf, lengthof(buf), "%s%s", _paths.data_dir, filename);
-	} else {
+	if (filename[0] == PATHSEPCHAR || filename[1] == ':') {
 		ttd_strlcpy(buf, filename, lengthof(buf));
+	} else {
+		snprintf(buf, lengthof(buf), "%s%s", _paths.data_dir, filename);
 	}
 
 	f = fopen(buf, "rb");
@@ -264,6 +264,31 @@ void AppendPathSeparator(char *buf, size_t buflen)
 	}
 }
 
+/**
+ * Allocates and files a variable with the full path
+ * based on the given directory.
+ * @param dir the directory to base the path on
+ * @return the malloced full path
+ */
+char *BuildWithFullPath(const char *dir)
+{
+	char *dest = MallocT<char>(MAX_PATH);
+	ttd_strlcpy(dest, dir, MAX_PATH);
+
+	/* Check if absolute or relative path */
+	const char *s = strchr(dest, PATHSEPCHAR);
+
+	/* Add absolute path */
+	if (s == NULL || dest != s) {
+		getcwd(dest, MAX_PATH);
+		AppendPathSeparator(dest, MAX_PATH);
+		ttd_strlcat(dest, dir, MAX_PATH);
+	}
+	AppendPathSeparator(dest, MAX_PATH);
+
+	return dest;
+}
+
 #if defined(WIN32) || defined(WINCE)
 /**
  * Determine the base (personal dir and game data dir) paths
@@ -307,11 +332,9 @@ void DetermineBasePaths(const char *exe)
 	/* Change the working directory to enable doubleclicking in UIs */
 	ChangeWorkingDirectory(exe);
 
-	_paths.game_data_dir = MallocT<char>(MAX_PATH);
-	ttd_strlcpy(_paths.game_data_dir, GAME_DATA_DIR, MAX_PATH);
+	_paths.game_data_dir = BuildWithFullPath(GAME_DATA_DIR);
 #if defined(SECOND_DATA_DIR)
-	_paths.second_data_dir = MallocT<char>(MAX_PATH);
-	ttd_strlcpy(_paths.second_data_dir, SECOND_DATA_DIR, MAX_PATH);
+	_paths.second_data_dir = BuildWithFullPath(SECOND_DATA_DIR);
 #else
 	_paths.second_data_dir = NULL;
 #endif
@@ -325,23 +348,10 @@ void DetermineBasePaths(const char *exe)
 	}
 
 	_paths.personal_dir = str_fmt("%s" PATHSEP "%s", homedir, PERSONAL_DIR);
+	AppendPathSeparator(_paths.personal_dir, MAX_PATH);
 #else /* not defined(USE_HOMEDIR) */
-	_paths.personal_dir = MallocT<char>(MAX_PATH);
-	ttd_strlcpy(_paths.personal_dir, PERSONAL_DIR, MAX_PATH);
-
-	/* check if absolute or relative path */
-	const char *s = strchr(_paths.personal_dir, PATHSEPCHAR);
-
-	/* add absolute path */
-	if (s == NULL || _paths.personal_dir != s) {
-		getcwd(_paths.personal_dir, MAX_PATH);
-		AppendPathSeparator(_paths.personal_dir, MAX_PATH);
-		ttd_strlcat(_paths.personal_dir, PERSONAL_DIR, MAX_PATH);
-	}
+	_paths.personal_dir = BuildWithFullPath(PERSONAL_DIR);
 #endif /* defined(USE_HOMEDIR) */
-
-	AppendPathSeparator(_paths.personal_dir,  MAX_PATH);
-	AppendPathSeparator(_paths.game_data_dir, MAX_PATH);
 }
 #endif /* defined(WIN32) || defined(WINCE) */
 
@@ -366,10 +376,7 @@ void DeterminePaths(const char *exe)
 	_paths.gm_dir        = str_fmt("%sgm" PATHSEP, _paths.game_data_dir);
 	_paths.data_dir      = str_fmt("%sdata" PATHSEP, _paths.game_data_dir);
 #if defined(CUSTOM_LANG_DIR)
-	/* Sets the search path for lng files to the custom one */
-	_paths.lang_dir = MallocT<char>(MAX_PATH);
-	ttd_strlcpy(_paths.lang_dir, CUSTOM_LANG_DIR, MAX_PATH);
-	AppendPathSeparator(_paths.lang_dir, MAX_PATH);
+	_paths.lang_dir = BuildWithFullPath(CUSTOM_LANG_DIR);
 #else
 	_paths.lang_dir = str_fmt("%slang" PATHSEP, _paths.game_data_dir);
 #endif
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index f91f947d6d..3236b52c3d 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -4941,7 +4941,7 @@ void LoadNewGRF(uint load_index, uint file_index)
 			if (c->status == GCS_DISABLED || c->status == GCS_NOT_FOUND) continue;
 
 			/* @todo usererror() */
-			if (!FileExists(c->full_path)) error("NewGRF file is missing '%s'", c->filename);
+			if (!FioCheckFileExists(c->full_path)) error("NewGRF file is missing '%s'", c->filename);
 
 			if (stage == GLS_LABELSCAN) InitNewGRFFile(c, _cur_spriteid);
 			LoadNewGRFFile(c, slot++, stage);
diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
index 6b58074964..3e3cfdc526 100644
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -40,7 +40,7 @@ static bool CalcGRFMD5Sum(GRFConfig *config)
 	size_t len;
 
 	/* open the file */
-	f = fopen(config->full_path, "rb");
+	f = FioFOpenFile(config->full_path);
 	if (f == NULL) return false;
 
 	/* calculate md5sum */
@@ -59,13 +59,14 @@ static bool CalcGRFMD5Sum(GRFConfig *config)
 /* Find the GRFID and calculate the md5sum */
 bool FillGRFDetails(GRFConfig *config, bool is_static)
 {
-	if (!FileExists(config->full_path)) {
+	if (!FioCheckFileExists(config->full_path)) {
 		config->status = GCS_NOT_FOUND;
 		return false;
 	}
 
 	if (config->filename == NULL) {
-		config->filename = strdup(strrchr(config->full_path, PATHSEPCHAR) + 1);
+		const char *t = strrchr(config->full_path, PATHSEPCHAR);
+		config->filename = strdup(t != NULL ? t + 1 : config->full_path);
 	}
 
 	/* Find and load the Action 8 information */
@@ -278,7 +279,7 @@ compatible_grf:
 extern bool FiosIsValidFile(const char *path, const struct dirent *ent, struct stat *sb);
 
 /* Scan a path for NewGRFs */
-static uint ScanPath(const char *path)
+static uint ScanPath(const char *path, int basepath_length)
 {
 	uint num = 0;
 	struct stat sb;
@@ -299,7 +300,7 @@ static uint ScanPath(const char *path)
 			/* Directory */
 			if (strcmp(d_name, ".") == 0 || strcmp(d_name, "..") == 0) continue;
 			AppendPathSeparator(filename, lengthof(filename));
-			num += ScanPath(filename);
+			num += ScanPath(filename, basepath_length);
 		} else if (sb.st_mode & S_IFREG) {
 			/* File */
 			char *ext = strrchr(filename, '.');
@@ -309,7 +310,7 @@ static uint ScanPath(const char *path)
 			if (strcasecmp(ext, ".grf") != 0) continue;
 
 			GRFConfig *c = CallocT<GRFConfig>(1);
-			c->full_path = strdup(filename);
+			c->full_path = strdup(filename + basepath_length);
 
 			bool added = true;
 			if (FillGRFDetails(c, false)) {
@@ -360,8 +361,10 @@ void ScanNewGRFFiles()
 	ClearGRFConfigList(&_all_grfs);
 
 	DEBUG(grf, 1, "Scanning for NewGRFs");
-	num  = ScanPath(_paths.data_dir);
-	num += ScanPath(_paths.second_data_dir);
+	num  = ScanPath(_paths.data_dir, strlen(_paths.data_dir));
+	if (_paths.second_data_dir != NULL) {
+		num += ScanPath(_paths.second_data_dir, strlen(_paths.second_data_dir));
+	}
 	DEBUG(grf, 1, "Scan complete, found %d files", num);
 }
 
diff --git a/src/stdafx.h b/src/stdafx.h
index 94c6da5ffe..a25789ecad 100644
--- a/src/stdafx.h
+++ b/src/stdafx.h
@@ -196,6 +196,7 @@
  * call to the same function and is not thread- or reentrancy-safe */
 #if !defined(STRGEN)
 # if defined(WIN32) || defined(WIN64)
+char *getcwd(char *buf, size_t size);
 #  include <tchar.h>
 /* XXX - WinCE without MSVCRT doesn't support wfopen, so it seems */
 #  if !defined(WINCE)
diff --git a/src/win32.cpp b/src/win32.cpp
index 4d99536d1e..fc119ce8ed 100644
--- a/src/win32.cpp
+++ b/src/win32.cpp
@@ -946,16 +946,30 @@ void GetCurrentDirectoryW(int length, wchar_t *path)
 }
 #endif
 
-void DetermineBasePaths(const char *exe)
+char *getcwd(char *buf, size_t size)
 {
-	_paths.personal_dir = _paths.game_data_dir = MallocT<char>(MAX_PATH);
-	_paths.second_data_dir = NULL;
 #if defined(UNICODE)
 	TCHAR path[MAX_PATH];
 	GetCurrentDirectory(MAX_PATH - 1, path);
-	convert_from_fs(path, _paths.personal_dir, MAX_PATH);
+	convert_from_fs(path, buf, size);
 #else
-	GetCurrentDirectory(MAX_PATH - 1, _paths.personal_dir);
+	GetCurrentDirectory(size, buf);
+#endif
+	return buf;
+}
+
+extern char *BuildWithFullPath(const char *dir);
+
+void DetermineBasePaths(const char *exe)
+{
+	_paths.personal_dir = MallocT<char>(MAX_PATH);
+	getcwd(_paths.personal_dir, MAX_PATH);
+
+	_paths.game_data_dir = BuildWithFullPath(GAME_DATA_DIR);
+#if defined(SECOND_DATA_DIR)
+	_paths.second_data_dir = BuildWithFullPath(SECOND_DATA_DIR);
+#else
+	_paths.second_data_dir = NULL;
 #endif
 
 	_paths.personal_dir[0] = toupper(_paths.personal_dir[0]);