Sorry for replying to this old post. I'm facing the similar issue. Can you please let me know if you were able to resolve this issue. Thanks in advance.
If you check the installation folder for the Migration tool you can find the ConvertLinks.aspx and codefile so you could easy add your own logging etc for debugging whats causing the error.
I am migrating a 4.62B site to CMS 5.2 using the Migration tool v220.127.116.11 (according to the .exe file). When I come to the permanent link conversion it stops working after some time - every 30 seconds displaying the same message
[Information] Processed links for 39401 properties, status inprogress
until I have to stop the migration manually. I have had the migration job running for over 10 hours and it won't get past this.
Anyone have any pointers as to how I can troubleshoot this and see which page/link/property migration goes awry? All comments are appreciated.