diff --git a/dlls/setupapi/misc.c b/dlls/setupapi/misc.c
index b1845b7e5c..825782856d 100644
--- a/dlls/setupapi/misc.c
+++ b/dlls/setupapi/misc.c
@@ -944,6 +944,13 @@ BOOL WINAPI SetupCopyOEMInfW( PCWSTR source, PCWSTR location,
         return FALSE;
     }
 
+    /* check for a relative path */
+    if (!(*source == '\\' || (*source && source[1] == ':')))
+    {
+        SetLastError(ERROR_FILE_NOT_FOUND);
+        return FALSE;
+    }
+
     if (!GetWindowsDirectoryW( target, sizeof(target)/sizeof(WCHAR) )) return FALSE;
 
     strcatW( target, inf_oem );
diff --git a/dlls/setupapi/tests/misc.c b/dlls/setupapi/tests/misc.c
index cee4823311..ea11a6cfd3 100644
--- a/dlls/setupapi/tests/misc.c
+++ b/dlls/setupapi/tests/misc.c
@@ -118,16 +118,22 @@ static void test_SetupCopyOEMInf(void)
     SetLastError(0xdeadbeef);
     res = SetupCopyOEMInf("", NULL, 0, SP_COPY_NOOVERWRITE, NULL, 0, NULL, NULL);
     ok(res == FALSE, "Expected FALSE, got %d\n", res);
-    todo_wine
-    {
-        ok(GetLastError() == ERROR_FILE_NOT_FOUND,
-           "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
-    }
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND,
+       "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
 
-    /* try nonexistent SourceInfFileName */
+    /* try a relative nonexistent SourceInfFileName */
     SetLastError(0xdeadbeef);
     res = SetupCopyOEMInf("nonexistent", NULL, 0, SP_COPY_NOOVERWRITE, NULL, 0, NULL, NULL);
     ok(res == FALSE, "Expected FALSE, got %d\n", res);
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND,
+       "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
+
+    /* try an absolute nonexistent SourceInfFileName */
+    lstrcpy(path, CURR_DIR);
+    lstrcat(path, "\\nonexistent");
+    SetLastError(0xdeadbeef);
+    res = SetupCopyOEMInf(path, NULL, 0, SP_COPY_NOOVERWRITE, NULL, 0, NULL, NULL);
+    ok(res == FALSE, "Expected FALSE, got %d\n", res);
     todo_wine
     {
         ok(GetLastError() == ERROR_FILE_NOT_FOUND,
@@ -140,11 +146,8 @@ static void test_SetupCopyOEMInf(void)
     SetLastError(0xdeadbeef);
     res = SetupCopyOEMInf(toolong, NULL, 0, SP_COPY_NOOVERWRITE, NULL, 0, NULL, NULL);
     ok(res == FALSE, "Expected FALSE, got %d\n", res);
-    todo_wine
-    {
-        ok(GetLastError() == ERROR_FILE_NOT_FOUND,
-           "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
-    }
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND,
+       "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
 
     get_temp_filename(tmpfile);
     create_inf_file(tmpfile);
@@ -153,11 +156,8 @@ static void test_SetupCopyOEMInf(void)
     SetLastError(0xdeadbeef);
     res = SetupCopyOEMInf(tmpfile, NULL, 0, SP_COPY_NOOVERWRITE, NULL, 0, NULL, NULL);
     ok(res == FALSE, "Expected FALSE, got %d\n", res);
-    todo_wine
-    {
-        ok(GetLastError() == ERROR_FILE_NOT_FOUND,
-           "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
-    }
+    ok(GetLastError() == ERROR_FILE_NOT_FOUND,
+       "Expected ERROR_FILE_NOT_FOUND, got %d\n", GetLastError());
     ok(file_exists(tmpfile), "Expected tmpfile to exist\n");
 
     /* try SP_COPY_REPLACEONLY, dest does not exist */