Always great to hear from new users and happy to hear you are having a positive experience (let alone, a loving one with MediaLab so far. Here are a couple pre-answers to your questions:

1. What exactly did you type in the custom (aka alternate) data location field? If it begins with a mapped drive letter (e.g., s:\, g:\) as it must (see Preferences in user's guide), do you have read/write permissions for that location? You do mention that this happens even if the data are written locally (i.e., with nothing typed in the alternate data location field). So hmmm... Again, check the read/write permissions on the folder you are targeting. If you do have full control of that folder, try backing up the whole data folder and delete it to start fresh. Note that if you copied the experiment folder to a CD and then copied it from there to another machine, the data folder (as well as ALL files and folders) will now be branded read-only. The data faq is located in the users guide under "Data" and can also be found online here:

http://www.empirisoft.com/medialab/help/data_faq.htm

2. Editing on a different machine than you will run on is no problem. Especially if the other machine is licensed. Is that the case? If not, there is a secret work around, but only for people who tell us they love the program (which of course, now includes you The secret trick to doing this without a license can be discovered by sending us another email telling us how much you like the program. Kidding of course--but do send us an email, and I'll elaborate on the workaround. Or... is this more of a practical question having to do with file and folder paths that might differ between machines? If so, check the user's guide regarding absolute vs. relative paths. Relative paths (generally) make it super easy to create the experiment on nay machine and then move it to any other one to run it--without concern for the actual location of the experiment folder.

You can also find this info online here:

http://www.empirisoft.com/medialab/h...file_paths.htm

Hope that helps,
Blair