There are known issues with re-installing FFXI, sometimes it's registry issues, othertimes it's versioning conflicts with files left on the hard drive. This can happen not only when moving from SE's installation to Steam's installation, but also when reinstalling the steam version--would imagine it holds true as well if re-installing an SE install. Can probably find a detailed how-to in the support site's knowledgebase.
Just ran a quick google search and got a hit right away on reinstalling the steam version:
http://support.na.square-enix.com/fa...n37rpiebpolbk3
At the very least, I'd look into their FAQ's at the support portal, or try to contact support either via e-mail or chat through the portal.KB Article: 58228
KB Category: [Technical Support]
KB Sub-category: [Known Issues] [Update / Patch] [ Installation] [Download] [Crash / Freeze]
I just reinstalled the Steam version of FINAL FANTASY XI and receive "Error code: POL-5312".
This error message is a result of the Steam version of FINAL FANTASY XI not being uninstalled correctly. The “ffxi” directory is not uninstalled when you select “Delete Local Content” from Steam. This is prohibiting the PlayOnline Viewer and FINAL FANTASY XI from updating if you reinstall the PlayOnline Viewer and FINAL FANTASY XI through Steam. This issue affects all Windows platforms.
To resolve the issue, please follow these steps:
1. Before reinstalling PlayOnline Viewer and FINAL FANTASY XI from Steam go to:
a. C:> Program Files (x86) > Steam > steamapps > common
2. Delete the “ffxi” directory
3. Start Steam
4. Reinstall the PlayOnline Viewer and FINAL FANTASY XI