Scheduled job sometime get fail status

[kwl1234]

I have scheduled a task to get delta change of the SQL server data and saved data as qvd. I get fail status when I scheduling the task on morning. But I restart the job manually, the job work properly. I checked script log, but i don't find any error on the script logs. i have not idea about the root cause of the problem.

I have found an error on system_engine log

AppSerializer: SaveApp_internal caught extended exception -1: Unknown error

[Bastien_Laugiero · Accepted solution]

Hello, 

If this is happening randomly with this error message I would look at any process that could potentially disrupt the save operation such as an antivirus like Windows Defender for example.

https://community.qlik.com/t5/Knowledge-Base/Antivirus-exclusions-in-Qlik-product-deployments/ta-p/1...

Hope this helps!