DraftSight 2026 SP3 – File association bug (double-click opens fail with "drawing not found")

Summary:
After a fresh installation of DraftSight 2026 SP3, double-clicking any DXF file in Windows Explorer fails with the error "Drawing '' not found," even though the file exists and can be opened without issues from within DraftSight (File > Open). The issue is reproducible on multiple independent machines and does not occur with DraftSight 2026 SP2.

Steps to reproduce:

1. Perform a fresh installation of DraftSight 2026 SP3

2. Set DraftSight as the default application for .dxf files

3. Double-click any .dxf file in Windows Explorer

Expected result: File opens normally in DraftSight.

Actual result: Error dialog: "Drawing '.dxf' not found."

Additional observations:

• The file can always be opened successfully via File > Open inside DraftSight, confirming the file itself and its path are valid and accessible.

• The issue occurs with every file and every file path tested — it is not specific to a particular file or location.

• The affected registry entry is HKEY_CLASSES_ROOT\\DraftSight.Drawing1\\shell\\open\\command, which contains:

  "C:\\Program Files\\Dassault Systemes\\DraftSight\\bin\\DraftSight.exe" /d '%1'

Note the single quotes around %1 instead of the standard double quotes.

• Manually correcting this value to use double quotes ("%1") had no lasting effect: the value appeared correct when re-checked in the registry, but Process Monitor confirmed that the actual process launched on double-click still used the incorrect single-quoted argument (/d 'C:\\...\\file.dxf').

• Re-associating .dxf files via "Open with > Choose another app" (which creates an independent HKEY_CLASSES_ROOT\\Applications\\DraftSight.exe registry entry) also did not resolve the issue.

• Running the same command manually via Command Prompt with correct double quotes opens the file without any error, confirming the core executable and command-line parsing work correctly when invoked directly.

• Two suspicious ShellEx handler CLSIDs are registered under DraftSight.Drawing1\\ShellEx ({8895b1c6-b41f-4c1c-a562-0d564250836f} and {e357fccd-a995-4576-b01f-234630154e96}), which may be intercepting or overriding the launch command independently of the registry command value.

• Workaround confirmed: Uninstalling SP3 and installing DraftSight 2026 SP2 immediately resolves the issue; double-click file opening works correctly again.

Conclusion: This appears to be a genuine bug introduced in the DraftSight 2026 SP3 installer/file-association or shell-extension component, not a local configuration or registry issue, given it is reproducible across independent machines and absent in SP2.

Request: Please confirm this as a known issue and advise on a fix or expected timeline (e.g., SP4), so we can resume using the latest service pack.