This is the XLSX counterpart of bug 165377. The additional problem is that Excel complains about the invalid file, and the named range gets removed. Perform steps from bug 165377, except save as XLSX at the end, or simply open attachment 199367 [details] from bug 165375, and save as XLSX. Open the XLSX in Excel. -> Excel complains about the invalid file. This particular named range is invalid, but I'm not sure if otherwise there are names that are valid in ODS and not in XLSX. Those should be considered as well. Noting the same comment as in bug 165377: This could be automatic, but it would be best to notify the user about the problem, which might help figuring out if invalid ranges are created in an obscure, unnoticed way. Observed using LO 25.8.0.0.alpha0+ (41ab24cecd6ad74312843f113d2faa13259cdb7d) and 3.3.0 / Windows.