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I had a heck of a time with the file ~/Library/Preferences/com.npvdata.client. Looked like it was some kind of cryptographic key file, and when I went to edit it, not only could I not change it, but also while I was editing it the file com.npvdata.client.swp and com.npvdata.client~ showed up, even though I was editing it in vi which doesn't create backup files. I had a really hard time deleting it, too.

I'm guessing this is part of some kind of copy protection or licensing scheme, but I'd like to know for sure where it is from, what it is for, and what danger there is, if any, of someone else getting a hold of it.

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vi is responsible of creating .com.npvdata.client.swp. – daniel Azuelos May 13 '13 at 12:32
This file is marked with the 'uchg' (user immutable) flag, which is why it was hard to delete (or edit). You can use the chflags(1) command to clear the flag for editing it (and to put it back on afterwards). – Alex Dupuy Dec 31 '13 at 18:26
up vote 1 down vote accepted

If my Googling-fu is stronger than yours, this appears to be linked to the Viscosity VPN client.

According to Viscosity technical support, Viscosity stores registration and trial information in this file, however it can be safely deleted if needed.

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Also, the file is most likely in the binary property list format. Xcode and the command-line defaults tool can typically read and write these files. – bneely Dec 15 '12 at 5:33
plutil -convert xml1 will convert this property list in an XML version 1. This format can be edited directly with vi without too many hidden side effects. – daniel Azuelos May 13 '13 at 12:36

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