I have a feeling this is coming form you Adobe Acrobat program and connected to Illustrator booting. Delete font capture temporary files:
1. Choose Start > Run, and type command in the Open text box. Click OK.
2. Type the following commands and press Enter after each command:
c:
cd\
del acr*.tmp /s
Note: Many lines of text will fill the Command.com window as this process runs. Wait for the process to complete (when the text has stopped for about 10 seconds), and then continue to the next step.
3. Type exit to close the Command.com window.
If you still have the issue:
Reinstall acrobat. https://www.experts-exchange.com/questions/24263847/How-do-I-stop-that-annoying-Font-Capture-applica...
Reset Your Font Cache
Remove this fileC:\Windows\System32\FNTCACHE.DAT
Search and delete all Adobefnt*.lst files
Reset Your Preferences.
Cmd-Opt-Ctrl-Shift when restarting AI on a Mac or Alt-Crtl-Shift on a PC to reset to the defaults.