No, having a popup will not directly affect your SEO or prevent Google from crawling your content, as long as the content is still accessible in the HTML source. However, if the popup does not offer users an easy way to close it, it may negatively impact your bounce rate. If visitors land on your website and are immediately forced to sign up or interact with a popup before they can view any content, many of them may feel frustrated. When users can't see the content they came for, they are more likely to leave the site quickly. This increases your bounce rate, which can indirectly signal poor user experience to search engines and potentially affect your search rankings over time.