The updates released by Microsoft on March 2016 (March patchday) may cause problems opening diagram files in e!Sankey. This issue was reported to us and we could confirm it on our own machines (Windows 7, Windows 10).
When trying to open an existing Sankey diagram file, or when creating a new diagram file, an error is prompted and the opening/creating of the file is aborted. The error message reads "Signature validation failed. File integrity compromised". See sample screenshot from e!Sankey 4 below.
We are not sure whether this problem occurs on all machines that have installed the March 8 security updates, or whether it occurs only on machines that have specific security settings.
[Update March 10: All e!Sankey versions 1,x, 2.x, 3.x and 4.0 seem to be affected. Problems have been reported for operating system Windows 7 and Windows 10]
Our staff is analyzing the issue at present, and we have likely identified which of the 13 Windows security updates may cause this problem for e!Sankey.
[Update March 9, 11 PM EST: KB3141780 and/or KB3135983 seem to be responsible for the problem. These security updates address a vulnerability in the Microsoft .NET Framework 3.5.1. Please see the link in post reply #1 below.]
Microsoft encourages all users to install the updates and labels them as important. Hence we can not call for abstaining from running the updates. Should you, however, be able to delay the Windows update for some days, you could avoid to run into a situation in which you are unable to work with e!Sankey.
We will be working hard to solve this issue, if we have a handle on it. We will keep you informed on all developments here in the forum. Our e!Sankey Help Desk will do its best to answer all your questions. However, as of present (March 09, 2016, 1 PM EST) we can not offer a solution.
[Update March 10, 2 AM EST: Using a system restore point might constitute a first quick solution. Please read post reply #2 below.]
[Update March 10, 6 AM EST: For Windows 7 users temporarily uninstalling KB3135983 seems to be a possibility to circumvent the issue. Please see the link in post reply #3 below.]
We very much regret this situation that has arisen with the latest Microsoft Update and apologize for all inconveniences caused to our e!Sankey users.