I've just installed QGIS 3.4.4. Each time I edit any layer, as soon as I select the vertex editor (single shapefile) I receive the 'unknown exception error'. The error then occurs with ANY edit in any layer. QGIS then crashes.
I have checked in ArcGIS and the shapefiles are clean. I have tried creating new (clean) projects with new (clean) shapefiles of just a simple two-node line but nothing fixes this error. Every shapefile I create or download is faced with the same issues.
I'm stuck - any suggestions?