Is libreoffice safe?
I'm using LibreOffice now, and I'm encrypting files of LO Write with VeraCrypt that have very personal content and I want to keep it secret. But I read about LO send to his web SO MUCH information, and I read an entry (that I cannot find again right now) that says he save so much secret information using LibreOffice like me, he have Comodo Firewall and he sees that the trusted files list of his Firewall, get double when he instals LO and sees that that files send a few KB of information. And he starts a difficult uninstall of LO all files.
Do you know anything about whether writing and opening files with LibreOffice is 100% secure? Should I change to OpenOffice or any other software?
The answer to your question - Is libreoffice safe is - Yes, You are safer with libreoffice. What you mention about telemetry (i.e. a program collecting information on how it is used and sending to the author's server) doesn't happen with libreoffice, but does happen with Microsoft Word and Apple's clone. OpenOffice should not be used! It has not been updated for the last 9 years. see full history at https://en.wikipedia.org/wiki/LibreOffice#History LibreOffice has its own questions website like this one. here is a link to the same question there: https://ask.libreoffice.org/en/question/89256/does-libreoffice-snoop-on-users-documents-really/ That said, all large programs today (and an office suite is huge!) have some sort of plugin system. LibreOffice has two such systems (that I know of): macros and extensions.
extension you have to actively install yourself. Just don't I guess. Macros are more complicated, they can come within a document you open. If I recall correctly, libreOffice will show a security warning when that happens allowing you to accept or not. And it can also be disabled globally on the preferences.