Real-time AV scanning hooks deep into the file system and can intercept/delay read (and/or write) requests while it does its scanning. It's possible that VFP may occasionally write a cursor to disk; delays due to scanning may get interpreted as "file does not exist" or "alias not found".

Disabling real-time scanning for just your temp file folder may be enough to test this theory.

There may also be other processes that hook into the file system e.g. so-called "real-time" backup/mirroring utilities.

READWRITE does not necessarily force a file to be written to disk, NOFILTER does. It might be interesting to experiment with adding NOFILTER to your query.

>Al --
>
>Antivirus scanning? Really? Am most curious why that might be a consideration.
>
>The odd thing is that this is intermittent, working correctly something well over 99.5% of the time ...
>
>Last of all, the cursor is created with ReadWrite, so there's no filtering involved.
>
>Jim
>
>>>I have been getting a few really odd errors with DataToClip. The following statement is used a few hundred times daily (in a single method -- it only appears once in that method.)
>>>

_vfp.DataToClip (lcStruct, 99999, 3)

>>>
>>>Once a week or so, a user will get an 'Alias not found' (error 13) message.
>>>
>>>I am now getting it in a session now as well, and I can verify that there is a indeed a cursor with that name:
>>>

Used(lcStruct) = .T.

>>>
>>>I have tried substituting different alias names, and they fail as well.
>>>
>>>An ideas what could be going on -- or any remedies?
>>
>>A couple of SWAGs:
>>
>>- test with real-time antivirus scanning disabled
>>
>>- is it possible the lcStruct is a filtered result set from something else? If so, how about creating it with NOFILTER?