Captools/net Documentation

"Canvas does not allow drawing" error

"Canvas does not allow drawing" error

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"Canvas does not allow drawing" error

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Captools/net's reporting uses certain parameters provided by the server computer's printer drivers during the report generation process. This is true even if the report will not eventually be printed.  Consequently, the computer on which the Captools/net Server Suite is installed needs to have a default printer driver installed, though it does not require a printer to be attached or turned on.


If there is no default printer driver on the server computer, or if the "Permissions" for the default printer driver are not properly set, users may encounter the error message "Canvas does not allow drawing" in the report generation log and the report will not appear on screen.  Sometimes this is the result of security software which has altered the permission settings of your printer driver.




1) Verify that a default printer driver is installed and specified on the Captools/net server computer.  If there is none, install one using the MS-Windows "File/Add Printer" option on the Windows "Printers and Faxes" control panel.


2) If a default printer driver is specified, verify its permissions by right-clicking on the driver in the "Printers and Faxes" control panel, selecting "Properties" and then "Security" to obtain the following:




First verify that printing is allowed for the Administrator users as shown above.  Then click on "Advanced", then "Advanced" again, then "Find Now" to add the "IUSR_ComputerName" item for your server computer to the list of your printer driver users:




Click "Ok" again on the following dialog.




Finally, verify that the "IUSR_" user has printing permission:





3) Lastly, try running reports to verify that these changes have resolve the "Unable to print to canvas" error.  If this resolves the error, but upon reboot of your computer, the error reappears, this is most likely the result of third party security software which is forcibly disabling the printer permissions.  We have found this to be the case with at least one version of a major brand of anti-virus software.  In this case we found that disabling the "Worm" protection on the anti-virus software prevented the disabling of the printer permissions.