Solved Cannot Attach Files to Gmail

Hi,
I'm a brand new member and am looking for some help. The problem started just yesterday. I cannot attach files of any type or size to email in Gmail. I'm using the latest version of Chrome on my desktop. If I select a file to attach, the progress meter starts to move, but it only gets about 2/3 of the way and then freezes. It usually just takes seconds for a file to load before sending the email. I've waited minutes and the loading process makes no further progress. I have cleared browsing history, cache, and cookies, and do not have a proxy running. The Windows firewall is disabled, but I do use Kaspersky for virus protection which, I believe, has it's own firewall. None of this helped. This also happened about a year ago, and somehow I fixed it, but I can't remember how. It might have had something to do with POP3 vs IMAP, but not sure. I don't recall if it was a Chrome issue or a problem with Gmail itself. Just before this started Chrome had a pop-up stating they had changed the display colors to be more compatible with various platforms, but I'm doubting that had anything to do with this issue. I'm running Windows 10. I hope someone can solve this for me. Please let me know if more information is needed.
Thanks!

Hello Bruce,
Thanks for the prompt reply. I disabled the Kaspersky Protection extension and the Google Docs extension, both one at a time and together. This had no effect. However, I found I was just not waiting long enough (with or without the extensions disabled). Turns out that a 7900kB jpeg file took 9 minutes to load, but it finally did and I was able to send the email with attachment. An 11 kB Excel file loaded almost immediately. So my problem all along wasn't that attachments would not load, but rather that they were taking a very long time.
I'm connected via an Ethernet card. I checked my internet speed: Download was 260 MBps and Upload was only 0.6 MBps. I disabled the Ethernet card and enabled WiFi and the Upload speed went up to 12 MBps. The 7900kB jpeg then took only about 10 seconds to load before sending. I didn't realize that during the process of attaching a file, it was actually being uploaded (I thought it was just a local process). So my real problem appears to be Ethernet upload speed.
I had this issue once before where the WiFi upload speed was much faster than Ethernet. I had then changed a setting in the Killer E2400 Gigabit Ethernet Controller App., and that fixed it. But I can't remember what I did in Killer, or why a setting would have changed recently. Any thoughts?
Thanks again.

I disabled the Prioritization Engine in the Killer E2400 Gigabit Control Center, and that restored the upload speed using the Ethernet card to the same level as when I use WiFi. I don't know why this fixed it, but it did. So I consider this issue SOLVED, at least for now. I will post again if the problem reoccurs.
Thanks for your time and suggestions.