>>>VFP 9/SQL Server app has been running smoothly for 10 years.
>>>Recently the client moved the LAN to AWS.
>>>Since then the client has been getting weird crashes that don't repeat.
>>>Today I got invalid seek offset while previewing a report. On a retry, all was OK
>>>Any suggestions?
>>
>>There are many ways that a "LAN" could be "moved" to AWS. Maybe if you could give us as many details as possible, someone could offer some ideas.
>
>Al
>
>Here is what Dave told me:
>
>
>*--Windows 2016 Server is what is being used in AWS. It’s using the latest technology. I can downgrade the SMB features on the servers which I have done with other customers still running outdated FoxPro applications but I was concerned about the impact of Business Processing that uses .NET. I do not know the impact of downgrading server features are going to have with .NET. Tell me if you want to proceed with the downgrades.

There's some useful ideas at http://fox.wikis.com/wc.dll?Wiki~InvalidSeekOffsetError1103~VB

Not sure what "downgrade the SMB features" means in this case. If he means to disable SMB2.x and SMB3.x (thereby forcing connections to use SMB1), I would not do that as certain features of Windows Server 2012 and later require those later versions of SMB.

You've given no information about where the VFP portion of your app is now running. Wherever it is, whether on individual user VMs on AWS or user sessions on an RDS server, the Alaska Software recommended registry changes should be applied: http://www.alaska-software.com/community/smb2.cxp

The Fox Wiki outlines several possible causes of ISO errors. My experience has mostly been with corrupt or out of date index files. If you have any "permanent" CDX index files and this error persists, you may want to replace with known good copies (e.g. from backup, even if out of date), then REINDEX.

If you're using remote printing through RDS you may want to make sure all applicable printer drivers on the RDS server and local machines are up to date. Easy Print can be just as it says on the tin but you may need to make sure it's configured properly.