diff --git a/src/sys/fileinfo.c b/src/sys/fileinfo.c
index fe096424..c7658d48 100644
--- a/src/sys/fileinfo.c
+++ b/src/sys/fileinfo.c
@@ -1775,6 +1775,11 @@ BOOLEAN FspFastIoQueryBasicInfo(
 {
     FSP_ENTER_BOOL(PAGED_CODE());
 
+#if DBG
+    if (!DEBUGTEST(50))
+        FSP_RETURN(Result = FALSE);
+#endif
+
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
     FSP_FSCTL_FILE_INFO FileInfoBuf;
 
@@ -1808,6 +1813,11 @@ BOOLEAN FspFastIoQueryStandardInfo(
 {
     FSP_ENTER_BOOL(PAGED_CODE());
 
+#if DBG
+    if (!DEBUGTEST(50))
+        FSP_RETURN(Result = FALSE);
+#endif
+
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
     FSP_FSCTL_FILE_INFO FileInfoBuf;
 
@@ -1841,6 +1851,11 @@ BOOLEAN FspFastIoQueryNetworkOpenInfo(
 {
     FSP_ENTER_BOOL(PAGED_CODE());
 
+#if DBG
+    if (!DEBUGTEST(50))
+        FSP_RETURN(Result = FALSE);
+#endif
+
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
     FSP_FSCTL_FILE_INFO FileInfoBuf;
 
@@ -1873,6 +1888,11 @@ BOOLEAN FspFastIoQueryOpen(
 {
     FSP_ENTER_BOOL(PAGED_CODE());
 
+#if DBG
+    if (!DEBUGTEST(50))
+        FSP_RETURN(Result = FALSE);
+#endif
+
     PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);
     PFILE_OBJECT FileObject = IrpSp->FileObject;
     FSP_FSCTL_FILE_INFO FileInfoBuf;