The Firefox profile folder where signons.sqlite resides is in the user account of the current Windows user account and shouldn't require any special permissions.

To which folder are you copying that file?

• http://kb.mozillazine.org/Profile_folder_-_Firefox

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

@cor-el: Thanks for helping. I was trying to copy it, as part of the whole profile, to an USB key, following instructions in 'Backing up your information' at http://support.mozilla.org/en-US/kb/Backing%20up%20your%20information

The copying worked, except for this file, but of course without that one loses half the value of the backup when one wants to re-install. (Incidentally I have not managed to find anything telling one how to re-install Firefox, so I was just going to copy the profile to the USB key, delete current Firefox and then copy the file back after a new installion of Firefox to whatever the new profile name might be - I hope that sounds like a rational procedure ? I have now discovered that there is a new Firefox, 10, so have upgraded to that in the meantime, hoping that this will solve the original problem of my interface with another website, since I have work to do: the 'signons.sqlite' /admin problem may therefore not be reproducible now, but if anyone has any thoughts about it, I would still be grateful in case I have not solved the original difficulty and this one does happen again)

Incidentally it wasn't a User Account Control request, just a little box with no attribution saying I needed admin authority.

Note to Moderator: the Bold and Italic buttons on this page do not seem to work, but produce respectively three and two inverted commas around the highlighted text

Moderator: okay, okay, they do work, just not while one is typing.

You need to copy the matching key3.db file as well.
The key3.db file stores the encryption key that is used to encrypt and decrypt the names and passwords that are stored in signons.sqlite.

@cor-el: Sorry, I did not make myself clear: I tried to move the whole profile directory, including all sub-files (among which was signons.sqlite), as one operation, not file by file (which wold have been remarkably tedious). The directory was moved, except for this one file: after transferring about 95% of the files (according to the line graph which was displayed), the transfer was interrupted for the curious message.

Eventually, after trying to give approval in various ways, I accepted that I could not transfer that file, but let the rest proceed to see what happened - which is how I know that everything else was transferred to the USB key.