During the work with binaries, IDA sometimes shows warnings to inform the user about unusual or potentially dangerous behavior or asks questions:
For some of such messages there is a checkbox “Don’t Display this message again”. If you enable it before answering or confirming the message (hint: you can press ‘D’ to toggle it without the mouse), IDA will remember your answer and use it the next time automatically. This can be observed in the log of the Output window:
Sometimes you may change your mind and want to pick a different answer. For example, you’ve answered “No” to the PDB symbols questions but later you do need to load PDB symbols for a file at load time (Note: it is still possible to do it after the fact using the File menu). Currently, there is no per message option but you can reset automatic answers for all of them using the menu Windows > Reset hidden messages…
After this, IDA will revert to the default settings and once again show all prompts and warnings, giving you a chance to answer differently.
IDA Help: Reset Hidden Messages