AutoCAD LT 2017 displaying unpickable lines all over the screen
When you open an older drawing file in AutoCAD 2015 or later, the drawing displays unwanted linework that cannot be selected or erased. The linework appears to be randomly displayed.
The following graphics cards have been reported to encounter this behavior:
- AMD ATI Radeon HD 3400 series (with 256 MB of RAM)
- AMD ATI FirePro 2260
- AMD ATI FirePro V3700
- AMD ATI Radeon HD 4200
- AMD ATI Radeon HD 4250
The issue is not exclusive to these cards.
Turning off hardware acceleration completely can also prevent unwanted linework from showing.
- In AutoCAD 2016 and newer: Before line smoothing can be disabled, the HQGEOM system variable must be turned off (that is, the “High Quality Geometry” checkbox in GRAPHICSCONFIG).
- In AutoCAD for Mac 2015: The LINESMOOTHING system variable does not exist; this solution does not apply to that version of the program.
- In AutoCAD for Mac 2016: LINESMOOTHING exists, but HQGEOM does not.