Thanks for posting. We understand that you're experiencing problems to reconnect to wireless networks once your system resumes from sleep mode.
Please make sure the wireless adapter power options are set to maximum performance. Here's how to do it on Windows 10*:
1- Right click on the battery icon at the taskbar and select Power Options (laptop) or open the Start Menu and search for "Power Options" (desktop).
2- Click on Change plan settings for the current power plan.
3- Select Change advanced power settings.
4- Set the power saving mode on the Wireless Adapter Settings to "Maximum Performance" on both "On battery" and "Plugged in" options and click Apply. On Desktops, you'll have a single setting instead of "On battery" and "Plugged in".
Please let us know if the issue persists after applying these changes.
Thanks for checking the power options for the adapter.
In order to better assist you, please provide us with the following details:
- Please download and run the https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows-?product=91600 Intel® System Support Utility and share the resulting report with us. This will allow us to check you system and wireless adapter settings.
- What's exact problem you get when the system resumes from sleep mode? Are you able to see the network but can't connect to it, or is not visible at all?
- On Device Manager, what's the status of your Intel® Wireless-N 7265?
Thanks for your reply.
We recommend uninstalling Intel generic drivers and installing the drivers provided by your OEM (Original Equipment Manufacturer). Here's how:
- Download and save the driver provided by your OEM http://www.dell.com/support/home/us/en/04/product-support/product/optiplex-9020-aio/drivers here. Change the Category to Network and download Intel 8260 7265 3165 7260 WiFi Driver.
- Uninstall the Intel® PROSet/Wireless Software.
- Open Programs and Features (Uninstall a program) from the Control Panel.
- Select Uninstall or Change and then Remove.
- When prompted, choose to discard settings.
- Uninstall your wireless driver. Windows* with an inbox driver may natively support some wireless adapters. You cannot uninstall an inbox driver. Proceed to the next step if you start seeing the same version of the driver installed automatically after it's uninstalled.
- Go to Device Manager.
- Expand the Network Adapters category.
- Right-click your Intel Wireless Adapter and choose to uninstall it.
- Make sure to select the option to Delete the driver software for this device.
- Clear out your temporary files.
- Press the Windows* key and R key simultaneously to open the run box.
- Type in: cleanmgr.exe and press the Enter key or OK.
- Place a check mark next to Temporary Files. You can leave everything else checked or unchecked.
- Press OK and wait.
- Reboot your computer.
- Locate the driver you downloaded back in Step 1. Run as administrator and follow the wizard to completion.
- (Optional Step) Apply the https://www.intel.com/content/www/us/en/support/network-and-i-o/wireless-networking/000024678.html Recommended Settings for Wireless Connectivity.
NOTE: Links to third party sites are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.
Please let us know the results.