You're trying to place a schedule (such as a Plant or Irrigation schedule) or another type of block. After the block has been placed in your drawing, CAD becomes laggy, or freezes or hangs for 30 or more seconds before you are able to pan or zoom again.
You may be using the Autodesk's Insert Block panel, or have used this panel in the past, and the Recent Blocks setting is trying to load past blocks, which are preventing other blocks from inserting properly.
With CAD open, type BLOCKMRULIST in the Command line and press Enter. Then set the value to 0.
To be extra thorough, navigate to the folder C:\Users\Username*\AppData\Roaming\Autodesk\20xx**\Rxx.x***\enu\RecentBlocks and clear the Recentblocks folder.
* Your computer username.
** Your year version of CAD.
*** This number will vary depending on your year version of CAD.
Still need to insert blocks using native CAD tools? Instead of using the Insert panel, try using the CLASSICINSERT command for inserting blocks into your drawing.
Your schedules and other blocks should now place instantly, without causing CAD to freeze or lag. If you still experience a lag, you may be dealing with corruption in the file or another issue. At this point, you can try cleaning the drawing file and all Xrefs.
Still experiencing a lag after cleaning your drawing and all Xrefs? Reach out to us via a technical support ticket and our team can help troubleshoot the issue.
For further information, see the official Autodesk article on this issue.