diff --git a/src/WINNT/afsd/cm_vnodeops.c b/src/WINNT/afsd/cm_vnodeops.c
index 2ab6c5b0c5..c7a4cabf41 100644
--- a/src/WINNT/afsd/cm_vnodeops.c
+++ b/src/WINNT/afsd/cm_vnodeops.c
@@ -3307,12 +3307,47 @@ long cm_Rename(cm_scache_t *oldDscp, fschar_t *oldNamep, clientchar_t *cOldNamep
     cm_dirOp_t newDirOp;
     fschar_t * newNamep = NULL;
     int free_oldNamep = FALSE;
+    cm_scache_t *oldScp = NULL, *newScp = NULL;
 
     if (cOldNamep == NULL || cNewNamep == NULL ||
         cm_ClientStrLen(cOldNamep) == 0 ||
         cm_ClientStrLen(cNewNamep) == 0)
         return CM_ERROR_INVAL;
 
+    /* 
+     * Before we permit the operation, make sure that we do not already have
+     * an object in the destination directory that has a case-insensitive match
+     * for this name UNLESS the matching object is the object we are renaming.
+     */
+    code = cm_Lookup(oldDscp, cOldNamep, 0, userp, reqp, &oldScp);
+    if (code) {
+        osi_Log2(afsd_logp, "cm_Rename oldDscp 0x%p cOldName %S old name lookup failed", 
+                 oldDscp, osi_LogSaveStringW(afsd_logp, cOldNamep));
+        goto done;
+    }
+
+    code = cm_Lookup(newDscp, cNewNamep, CM_FLAG_CASEFOLD, userp, reqp, &newScp);
+    if (code == 0) {
+        /* found a matching object with the new name */
+        if (cm_FidCmp(&oldScp->fid, &newScp->fid)) {
+            /* and they don't match so return an error */
+            osi_Log2(afsd_logp, "cm_Rename newDscp 0x%p cNewName %S new name already exists", 
+                      newDscp, osi_LogSaveStringW(afsd_logp, cNewNamep));
+            code = CM_ERROR_EXISTS;
+        }
+        cm_ReleaseSCache(newScp);
+        newScp = NULL;
+    } else if (code == CM_ERROR_AMBIGUOUS_FILENAME) {
+        code = CM_ERROR_EXISTS;
+    } else {
+        code = 0;
+    }
+    cm_ReleaseSCache(oldScp);
+    oldScp = NULL;
+
+    if (code) 
+        goto done;
+
     if (oldNamep == NULL) {
         code = -1;
 #ifdef USE_BPLUS