diff --git a/win32ss/user/ntuser/scrollbar.c b/win32ss/user/ntuser/scrollbar.c
index ece40873a4..f0e7fb82cf 100644
--- a/win32ss/user/ntuser/scrollbar.c
+++ b/win32ss/user/ntuser/scrollbar.c
@@ -520,6 +520,8 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
    psbi = IntGetScrollbarInfoFromWindow(Window, nBar);
    Info = IntGetScrollInfoFromWindow(Window, nBar);
    pSBData = IntGetSBData(Window, nBar);
+   if ( !pSBData )
+       return 0;
 
    /* Set the page size */
    if (lpsi->fMask & SIF_PAGE)
@@ -703,6 +705,8 @@ co_IntGetScrollBarInfo(PWND Window, LONG idObject, PSCROLLBARINFO psbi)
 
    sbi = IntGetScrollbarInfoFromWindow(Window, Bar);
    pSBData = IntGetSBData(Window, Bar);
+   if ( !pSBData )
+       return FALSE;
 
    IntGetScrollBarRect(Window, Bar, &(sbi->rcScrollBar));
    IntCalculateThumb(Window, Bar, sbi, pSBData);