Hi Jörgen,
At present we do not have the support for disabling open, save and print buttons in the built-in toolbar of PdfViewerControl in windows forms. However we can achieve this by using Custom Toolbar sample which is available in Syncfusion Products.
We have attached a custom toolbar sample with disabled open, save and print buttons in the following link:
Custom Toolbar
After running the sample, please check the “Show Custom Toolbar” radio button which is at the top-left.
Please try this sample and let us know whether it suits your requirement.
Regards,
Deepak G