There are some instances where antivirus (AV) products can cause the P11D Organiser to not work as expected - this is often related to realtime scanning/protection which can cause execution or read/write access issues. There are many AV products out there and we will give advise as a general guide on how to prevent these problems from occuring.


While various errors can occur, in this illustration, we are preparing a P46(car) submission to HMRC and on clicking "Prepare Submission" you get the following error:

This can be the AV product preventing the P11D Organiser from writing/creating a file (or files) within the application's directory structure. The software needs to be able to write files and data to function correctly. 

To solve the above and similar issues please see the guide below.


We highly recommend that you whitelist the P11D root directory recursively (that is, all directories/subdirectories) within the P11D organiser installed path. Where this is installed will vary dependant on your setup. but an example could be: C:\P11DOrganiser\P11D 

This would mean you would want to whitelist: C:\P11DOrganiser\P11D\* 

Note: the wildcard (*) in many antivirus products, wildcarding is often supported either manually or via an option which will denote that everything within the chosen directory is excluded. While we would encourage yourselves to look into how to do this for your chosen AV solution, we have linked some guides on how to do this with some of the most popular products:




Windows Defender


Kaspersky Security Centre

If there is further assistance needed please contact the P11D support team.