Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
What version of Mac OS X are you using ? What exact error are you getting ?
Hi there, It is possible that Safari is infected with malwares or adwares which is causing the Safari to crash. Close Safari. Hold down Shift key on your keyboard and open Safari. Click on Safari menu and select Clear History and Website Data. On the dropdown next to Clear, select All History and click Clear History.
Then click on Safari menu and select Preferences. Then click on Privacy tab. Click Remove All Website Data. Click Remove Now. Restart Safari. Then download, run and scan your Mac with this application, Malwarebytes --> https://www.malwarebytes.org/mac-download/
This will find and remove all adwares/malwares from your Mac if any. If you are unable to download from the above website, then download the Malwarebyte Anti Malware application from here -->http://wikisend.com/download/882684/MBAM-Mac-184.108.40.206 (2).dmg
After downloading, open the application and scan your Mac with it. If it finds something, remove them all. Then open Safari and try to attach something.
Let me know how it goes.