I haven't been able to find any meaningful advice on how to delete future-dated calendar entries. I acknowledge that such a need would be more of a power user requirement but if you're ever going to dabble in synchronisation with Google Calendar then you will more than likely encounter a situation where a recurring calendar entry has been repopulated as a string of independent events that potentially go on "forever".
Obviously if you only have a handful of entries like this then it's probably easiest to just filter your calendars that you show on GOOGLE CALENDAR and then manually delete the entries you want via AGENDA VIEW. If, on the other hand, you have scores or hundreds of such entries (if it's repeated daily or weekly) the quickest way to do this (and cheapest) is via a tool called GCalToolkit, using the free Online Tool.
If you want to delete future events then follow these steps:
- Define the START DATE and END DATE (you can only pick a set number of years into the future per selection; to get further just click on the latest year available and then repeat the process and the NEXT set of years will be available).
- Click on the START filter (first column) to order the events by their chronological order and not by their create date
- Click on the REMOVE checkbox at the start of the series you want to remove
- While holding SHIFT click on the REMOVE checkbox at the end of the series you want to remove
- Click "SYNC to GCAL" and give it some time to update.
You can also use this tool to perform mass deletions and duplicate removals. The duplicates are nicely highlighted so it makes life a lot easier.
Alternative solutions to the above tool include Mozilla Thunderbird + Lightning addon. Just add in either Provider for Google Calendar plugin or CalDAV (or similar) which will allow you to add all your calendars to Thunderbird and manipulate them there using the Lightning search functions.