I have just completed the migration from WLM to Microsoft Office Outlook. We did this as Microsoft will not support WLM from 2017.  We chose Office Outlook as the functionality in the new Microsoft Mail leaves much to be desired.  Note that functionally of the process is governed by WLM.

Suggest it is in Microsoft's interest to fix these as I'm sure many more will be exiting WLM.

We followed the process outlined in:  https://support.microsoft.com/en-gb/kb/980534

There are a couple of bugs that we discovered, and some aspects which need clarification.

1. The size of the email folders can cause the migration to fail.  There is no finite way to find out what the limitation is at present, the best we could do is trial and error, by splitting the size of the larger folders.

2. Also some sub-folders names are corrupted, not the end of the world as enough is left to determine what the original folder name was.

We also found that in transferring contacts the email addresses weren't copied across, unless we selected additional options (item 11) and explicitly selected/mapped the field.

Hope (i) this helps folks, and (ii) persuade MS that it is in their interest to sort these bugs.