diff --git a/webif/html/diskspace/diskspace.jim b/webif/html/diskspace/diskspace.jim
index d21b767..5cd88c8 100755
--- a/webif/html/diskspace/diskspace.jim
+++ b/webif/html/diskspace/diskspace.jim
@@ -9,6 +9,11 @@ lassign [system diskspace 1] size used perc free fperc tsrbuf tsrused
 set tsrreserve $($tsrbuf - $tsrused)
 # Adjust values to account for the TSR reserve
 set free $($free - $tsrreserve)
+# In case the reserve has been over-committed
+if {$free < 0)} {
+	# avoid displaying negative free, or used > available
+	set  free 0
+}
 set used $($size - $free)
 
 set dbs 0