You can allocate more RAM to TOS:
You drag the icon to the Applications folder. You attempt to open it. macOS refuses. "“thinkorswim” cannot be opened because the developer cannot be verified." You navigate to System Settings > Privacy & Security. You click Open Anyway . You enter your admin password. You are opening a portal to the NYSE and NASDAQ, and your Mac is warning you that the portal is unregulated. You proceed. install thinkorswim
Before the binary hits your hard drive, you are redirected to the web portal. This is the first filter. The modern interface of the TD Ameritrade site (or Schwab, following the merger) is a stark contrast to the desktop application you seek. It is clean, web-based, and deceptively simple. You can allocate more RAM to TOS: You