Make sure you're using XAMPP 1.8.3.

XAMPP 1.8.2 had this as a known bug.

I'm new to Mercury Mail as it came bundled with XAMPP and I would like to use it to send emails from my localhost. I'm using Mercury Mail/32 version 4.52.

I'm trying to get it set up and I am noticing that I am unable to save my configuration settings.  Specifically, I would like to change  Mercury->configuration->Protocol modules. If I check or uncheck items, close Mercury and reopen it, all the items are back to their original setting.  I'm trying to get MercuryC enabled.

Am doing something wrong?   Thanks!

Make sure you have write access to the Mercury dir.

Check that mercury.ini is not marked read only. 

Thank you both for your answers. I am stumped at the moment.  I checked the attributes and indeed they are read-only but they seem to be protected. Nothing I try seems to work to make them writable. Any thoughts would be appreciated.

This seems like a permissions issue.  Check the documentation that came with Xamp and see what user/rights it was installed with.  As administrator you could take ownership and change the r/o flag.

Normally Mercury needs to run as administrator (or local system if running as a service).

I am logged in as admin of my Windox XP Pro system. XAMPP does not really come with documentation. They only have FAQs in Eglish, everything else seems to be in German. I have searched their forums quite a bit.

On the other hand, I am able to edit the mercury.ini file so I have been doing that. Thanks for all the helpful responses!

I have the same problem. I continue looking for an answer to fix it.

I have just seen that mercuryc is not in the protocol section of mercury.ini.

Good, I have seen a possible solution: I have done the changes by mercury.ini. I have disabled the libraries that I didn't want in Protocol section and I have write the library that I wanted (it was not in the section).

Warning: there is a virus with the same name that mercury.dll and mercuryc.dll! The file mercuryc is installed with mercury and there is in the folder. Be care with change it by another that you download from Internet. 

P.D. Sorry for reliving an old post. 

If running a recent verison of Mercury (like 4.74) there shouldn't be any problem with changing modules using the GUI: Configuration menu, Protocol modules