This sounds like a corrupt download for the installer, which is possibly due to temporary Internet files causing the issue. First, delete the old download, if it appears in Applications, remove it by dragging it to the trash, and restart the computer, Then, clear the cache for your Internet as follows:
Here’s a quick introduction into how to delete browser cache on Mac.
Chrome clearing cache tutorial
Here’s how to clear browser cache in Chrome manually:
- Click the burger icon in the top right corner of Google Chrome browser.
- Choose Settings.
- In the left menu, choose History.
- “Clear browsing data.”
- Deselect all, but Cached images and files.
- Timewise, choose the beginning of time.
- Hit “Clear browsing data” button.
Firefox clearing cache tutorial
Here’s how to delete cache in Firefox manually:
- In the History menu, select Clear Recent History.
- From the drop-down menu with time range, select the desired range; to clear all the cache, select Everything.
- Next, click the down arrow next to Details and choose only Cache.
- Click Clear Now.
- Exit/quit all browser windows and re-open the browser.
Safari clearing cache tutorial
Safari is a little trickier than the rest of the browsers. You could remove caches together with all the other website history through History — Clear History in menu bar.
But if you need more precision, here’s how to empty cache on Safari browser:
- In the top menu, choose Safari.
- Click Preferences.
- Choose the Advanced tab.
- Enable Show Develop menu in menu bar.
- Now go to Develop in menu bar.
- Choose Empty caches.
Make sure you close/quit the browser and restart it after clearing cache.
Download the Installer again, and try it one more time, if it fails, it is time to consider CCleaner, which is available at http://www.piriform.com/ccleaner
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