Snapchat sometimes shows problems in editing or opening old memories. It may be because of a poor internet connection or due to a space shortage in your device. If you are facing this problem, then connect your device to an excellent internet connection, and then clear cache from your device instead of deleting any snap or video from Memories.
Other than this, there are some steps to edit snaps from your Memories.
Step 1: Open a snap from Memories and hold it for one or two seconds. There will be options on the screen; select the Edit Snap option.
Step 2: Snapchat will take you to the editing screen, and now you can edit your snap by following the same steps we have listed above.
Step 3: After tapping on Done, your edited snap will again save to your Memories. Moreover, you can also shift it or export it to Camera Roll.