Hi Paul,
Thanks for the response. I was under the impression that point number 1 (sparse files with NetApp) was the case, so I don't have an issue with that.
I opened a case with Symantec partner support concerning the Visio issue. What's strange in this case, is that I've watched what happens to the file when Visio retrieves it. The whole file gets retrieved (in fact, just after it was retrieved from the File Vault store, I copied it, and it was intact) but then Visio actually overwrites it on the file system and I get a blank drawing, so this gives me something to go on as well.
Thanks very much,
10e