Hello R S 87,
From your description, may I understand that the Archive folder like the following screenshot is missing?
If so, to help you with your problem, you can try the following methods to see whether it works for you:
1. Click
button at the left side and choose Folders, then check whether the Archive folder is included in the list.
2. Close Outlook and press Win + R to open Run dialog. Then type outlook.exe /resetfolders and click OK. This command will restore missing folders for the default delivery location.
3. Please make sure your Outlook is up to date. To do that, go to File > Office Account > Update Options > Update Now.
4. If convenient, you can try re-adding your account into Outlook to see if the folder comes back.
If the Archive folder still disappeared, to further assist you, please provide the following information to me:
1. The screenshot about your Outlook version. To get it, please click File > Office Account, in Product Information section, you can see the version about Outlook like the following screenshot:
2. If you are an Office 365 for Business user, please go to Outlook Web App and check if the Archive folder exists.
Regards,
Seven