Outlook附加Exchange账户已发送文件夹EntryId运行时变更求助

问题背景 #

我使用Outlook时遇到已发送文件夹（Sent Folder）异常问题：名下有两个Exchange账户，默认账户运行一切正常，但附加账户出现EntryID变更的异常情况。

附加账户初始EntryID信息 #

outboxMailEntryID = 00000000A24FEAFFFFB93C47A13126365D132558010010E2685A8E0AC440B14F77F5EE5275A5000000BBA**800000**0
sentMailEntryID = 00000000A24FEAFFFFB93C47A13126365D132558010010E2685A8E0AC440B14F77F5EE5275A5000000BBA7FF0000

EntryID变更详情 #

附加账户下名称为Gesendete Elemente的已发送文件夹EntryID在运行过程中发生变更：

• 变更前：

IsOutputExtended check folder.Name = **Gesendete Elemente** folder.EntryID = 00000000A24FEAFFFFB93C47A13126365D132558018010E2685A8E0AC440B14F77F5EE5275A5000000BBA**8000000**

• 变更后：

IsOutputExtended check folder.Name = **Gesendete Elemente** folder.EntryID = 00000000A24FEAFFFFB93C47A13126365D132558018010E2685A8E0AC440B14F77F5EE5275A5000000BBA**8000100**

用于判断文件夹类型的代码 #

以下是我编写的判断文件夹类型的C#代码片段：

private static bool IsOutputExtended(MAPIFolder currentFolder)
{
  PropertyAccessor propAcc = null;
  Microsoft.Office.Interop.Outlook.Folders folders = null;
  MAPIFolder rootFlder = null;
  Store store = null;

  if(currentFolder == null)
    return false;

  try
  {
    store = currentFolder.Store;

    const string PR_IPM_OUTBOX_ENTRYID = "http://schemas.microsoft.com/mapi/proptag/0x35E40102";
    const string PR_IPM_SENTMAIL_ENTRYID = "http://schemas.microsoft.com/mapi/proptag/0x35E20102";
    
    rootFlder = store?.GetRootFolder();
    folders = rootFlder?.Folders;

    string sentMailEntryID = "";
    string outboxMailEntryID = "";
    propAcc = store?.PropertyAccessor;

    try
    {
      if (propAcc != null)
      {
        object entryOutbox = propAcc.GetProperty(PR_IPM_OUTBOX_ENTRYID);
        outboxMailEntryID = propAcc.BinaryToString(entryOutbox);
        object entrySend = propAcc.GetProperty(PR_IPM_SENTMAIL_ENTRYID);
        sentMailEntryID = propAcc.BinaryToString(entrySend);
      }
    }
    catch(Exception ex)
    {
      CobraMain.Logger.Warn("Error in IsOutputExtended by Check PR_IPM_OUTBOX_ENTRYID and PR_IPM_SENTMAIL_ENTRYID for " + currentFolder.Name, ex);
    }

    if(currentFolder.EntryID == sentMailEntryID || currentFolder.EntryID == outboxMailEntryID)
      return true;
....

请问该问题的原因是什么？感谢解答。

内容的提问来源于stack exchange，提问作者Viktoriusrex