outlook 主旨無法排序 "無法依據這個欄位排序"

 有使用者反應在outlook收件匣中，無法依主旨排序信件，會出現"無法依據這個欄位排序"的錯誤訊息。

其他欄位排序卻都沒問題，一開始用這個錯誤訊息去找出來的解法，都沒什麼用，也沒在細查，因為電腦有其他比較麻煩的問題，所以這個就先不管。

等電腦其他outlook問題解決時，這問題還是有，又在看了一下，突然發現，上面欄位不是"主旨"，而是"工作主旨"，所以就點開欄位設定，順便看了一下其他outlook，正常的話，都是顯示主旨這個欄位。

使用者不知怎麼弄的，變成工作主旨，這個欄位本來就是無法排序的，只要把它改回主旨就行了。

Users reported that they were unable to sort their emails in Outlook's inbox by subject, and encountered an error message saying "Cannot sort by this column."

Sorting by other columns worked without any issues. Initially, the suggested solutions found using this error message were ineffective, and further investigation was not conducted due to other pressing computer issues.

However, even after resolving the other Outlook problems on the computer, this sorting issue persisted. Upon closer examination, it was discovered that the column header was not "Subject" but rather "Subject (Work)." The column settings were opened, and a comparison with other Outlook instances revealed that the normal display should be "Subject."

It was unclear how the user had changed it to "Subject (Work)," but this column was inherently unsortable. Simply changing it back to "Subject" resolved the issue.