From version 13, users can alter the menu for "Check for Update" by editing the menu.xml file. This option does not perform any updates on ChemDraw when you click on it.
The option was removed for version 19.1 and later.
For ChemDraw 19.0 you need to edit the menu.xml file present in the following location:
To remove "Check for Update" please do the following:
1. Copy menu.xml present in the following location to a different location (say at your Desktop)
For v19.0, the folder is located at:
2. Now open the menu.xml file present in the above location in Notepad and search for "Check for Updates" and remove the XML tag present in the "&Check for Updates".
3. Save the file and relaunch ChemDraw. You should no longer see "Check for Updates" under the Help menu.
For any other version of ChemDraw, please change the path to match the version that you are using (i.e ChemOffice2018, ChemOffice2017,etc).