SharePoint randomly displays web part error

Question

I am noticing that on all pages sometimes SharePoint doesn't load web part and displays the following message:

Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Microsoft SharePoint Foundation-compatible HTML editor such as Microsoft SharePoint Designer. If the problem persists, contact your Web server administrator.

Refreshing the page solves this problem.

And another weird behaviour I noticed today. Let's say I have a page in which I have placed Content Editor web part. I open the page and do not turn of my computer and go home. Next day when I check that page again (I don't refresh it, nothing, it's just there already opened which I did yesterday) it shows the above web part error message.

Why is this happening?

Answer 1

This is quite a generic error message. And a generic answer would be - it is happening as it takes to long to load a query. In order to see the limit of a query timeout you can run powershell command:

$farm = Get-SPFarm
$farm.XSLTTransformTimeout

If it is 1 sec, you may want to change it to 5 (or whatever you think is reasonable). Use the powershell command:

$farm = Get-SPFarm
$farm.XSLTTransformTimeout = 5
$farm.Update()

If that won't help you have to try to find if there is anything specific that causes the timeout error. In my case it was a SharePoint bug - if you backup/restore a site collection, you get this error when displaying All Items views. I created a view loading 20 items at a time instead of all and it fixed the issue.