On September 29th, according to a post by technology media AppleInsider, some users reported that after upgrading older models such as iPhone 17 to the newer iOS 27, as well as on iPhone 18, Pro and iPhone 18 Pro Max, there were brief instances of slow performance. It has been basically confirmed that this issue is related to the creation of the "focus" ( Spotlight ) index.

According to feedback from community users, after upgrading models such as iPhone 17 to the iOS 27 system, as well as on models iPhone 18, Pro and iPhone 18, Pro Max, there may be instances where response times slow down.

The media pointed out that this situation is expected to be related to the Spotlight indexing function of iOS. The system will scan files, folders, applications, documents, emails, information, contacts, photos, music, podcasts, memos, and system settings, and establish a local search directory.

After the indexing is completed, Spotlight can find emails, files, and memos more quickly. Siri AI can also read information such as flight times from emails or calendars based on the index and return the relevant content.

Apple explains that the indexing process is entirely performed locally on the device, and the generated index is also stored on the device. The iOS process will continue to update the index. Apple clearly states that the first time the index is created, the task is the largest in scale, and users are most likely to notice a decrease in performance at that time.

The indexing time depends on the amount of data stored on the device. According to Apple's support documents, the indexing of Spotlight may take several hours or even days. This media observed that the actual waiting time for some devices was about a week.

The official Apple update log content is as follows:

About the process of establishing the "Focus" index

"Focus" will create an index for your device to help you search through its contents. The index is established when you set up the device for the first time, after installing software updates or upgrades, and whenever there are changes to the data on the device. For example, the index will be updated when you install a new App that supports indexing content, or when you receive new emails or text messages. Depending on the amount of data on the device, the process of creating the "Focus" index can take several hours or even days. Once the index is created, subsequent incremental updates will be much faster. The index creation process will be completed more quickly in the following situations: your device is in an idle state; your device is powered on; and your device is connected to the internet via Wi-Fi or Ethernet, allowing emails or other data to be downloaded as needed for index creation.

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