In the early 2000's, many security professionals called for you to turn off the preview feature of your email client.
Simply previewing an email could be dangerous! With a modern email client, you can preview all the emails you want.
If you do not remember what happened in the past, you will say that it is safe
There are many articles advising you to turn off preview. Many websites considered its use of the preview to be a bad idea. They often did not explain why, other than saying "you can open an email that you really do not want to open."
The truth is that a virus or other dangerous program can be transmitted to your computer if you open an infected email. To be precise, this was a problem for a while before the beginning of the new millennium.
For a short time, it was considered dangerous to open messages and, consequently, to use the preview window, unless one is sure that the e-mail is secure.
But the biggest email developers of the day, such as Microsoft, Pegasus, Eudora and Apple (Gmail did not exist yet), took the matter more seriously.
Within a few years, the problem virtually disappeared because all mail clients stopped allowing code execution when an email was opened. No mail client allows code execution when you open an email. So, unless you are using a very old e-mail client (consider Outlook Express 2000 on a Windows 98 computer), your e-mail program will simply not allow code to run when you open an email.
The real danger
In addition, all major email account providers, including Microsoft, Apple, Gmail and Yahoo! have sophisticated virus and malware detection tools that prevent malicious applications from accessing your inbox anyway.
This does not mean that malicious applications do not circulate via email. But it requiresto be open an attachment or click on a link. So there are still voices that still say that preview windows are a serious danger. But they probably miss them…
The problem no longer seems to exist, so by disabling the preview window, the only thing you do is make your life harder.
As mentioned earlier, opening emails is safe. The danger comes from the links of "fishing" and the opening of dangerous attachments. These risks are the same whether you use Outlook or Gmail email client.
Yes, it is safe to use the preview window and you can enjoy the convenience it gives you.