Could you tell us how you are powering your Roku device? Is it connected to the USB port of the TV or to a wall outlet? In some cases, the USB power provided by the TV is not sufficient to power the device. Even though your Roku device may appear to be working, running with insufficient power can lead to instability, crashing, and other unpredictable behavior.
Using the included power cord and power adapter, we suggest plugging your Roku into a working power outlet in the wall. Powering it through a power outlet in the wall has the additional advantage that your Roku player will not need to power up every time you turn on your TV. This means your Roku player will be up and running faster than it would be connected to a TV.
Check and see if your Roku software updated to 10.5.0, if so, many of us have been having problems since this update. If it don't say 10.5.0 then don't update it yet because you may experience more problems than you are having now. To check Roku software version go to Settings - System Update (move cursor to right and you will be able to see the software version but DO NOT UPDATE if it is under 10.5.0). Come back to your post and provide the following information:
Roku device model, serial number, device ID, and software OS/version which all can be found Settings - System - About (move cursor to the right and you will be able to see all of the above).
If issue is occurring on certain channels, go back to home page, hit the * button on the highlighted app (Netflix for example) and it will show you the version and build numbers.
Try loading the apps that are acting up and when it does, press the Home button 5 times and immediately after, the Back Arrow button 5 times.
Post exactly what you are seeing (errors, loading issues) on the affected apps.