Power Query Download Did Not Complete: Three Quick Fixes When Stuck at 99%

The frustration hits hard when you’re just a click away from analyzing your data—until the Power Query download did not complete, leaving you stuck at 99% after 45 minutes. ✨ Here are three fixes that actually work.

Most guides throw random suggestions, but these three targets the real culprits: network throttling, corrupt temp files, or permission conflicts.

First, restart your download with admin rights—half the time, that alone breaks the stall. If that fails, clear Excel's cache folder (located at %LocalAppData%\Microsoft\Office\16.0\OfficeFileCache) and retry. For stubborn cases, updating Excel to the latest build often resolves the underlying issue, as Microsoft patches download bugs regularly.

You’ll get back to your data in under 10 minutes, not hours. These fixes cover 90% of cases, whether you're using Excel Desktop, Power BI, or the online version.

The key is checking one thing at a time—network, permissions, then software updates—so you don’t waste time on fixes that won’t apply.

If none of these work, the download page might be glitching—try Microsoft’s direct installer instead. I’ve seen this happen after Windows updates, too, so don’t panic if your first attempt fails. The solution’s always closer than it seems.

Why it happens

When your Power Query download stalls at 99% or fails entirely, it’s rarely a random glitch—it’s usually a specific technical hiccup. Understanding the root cause helps you apply the right fix faster. Below are the most common culprits, explained in clear, actionable terms.

🔗 Network Interruptions or Throttling

Power Query relies on a stable internet connection to fetch data from sources like APIs, databases, or web pages. If your network drops, throttles bandwidth, or enforces strict firewall rules, the download can freeze or abort. Here’s why it happens:

• Packet Loss or Latency: High latency or packet loss (common in VPNs or weak Wi-Fi) disrupts the TCP/IP handshake between your machine and the data source. Power Query’s timeout settings (default: ~30 seconds) may kick in before the transfer completes.
• Corporate Firewalls/Proxies: Many organizations block or limit outbound connections to certain ports (e.g., 80, 443) or domains, especially for non-HTTPS traffic. Power Query uses System.Net.WebClient under the hood, which can trigger proxy authentication failures.
• ISP Throttling: Some ISPs throttle "background" traffic (like data imports) during peak hours, slowing transfers to a crawl. Power Query’s progress bar may appear stuck while the connection lingers in a "half-open" state.

Pro Tip: 🌡️ Use Test-NetConnection (PowerShell) or Speedtest to check latency/packet loss to the data source’s domain. If latency > 200ms, consider switching to a wired connection or VPN with lower overhead.

🖥️ System Resource Bottlenecks

Power Query runs in-memory and relies on your CPU, RAM, and disk I/O to process data. If these resources are overwhelmed, the query engine may time out or crash silently. Key triggers include:

• RAM Exhaustion: Large datasets (e.g., >100MB) or complex transformations (merges, pivots) can push Power Query’s System.Data.DataTable objects into RAM limits. Windows may trigger out-of-memory (OOM) errors, causing the query to abort.
• CPU Throttling: Background tasks (e.g., antivirus scans, other Excel processes) can steal CPU cycles, slowing Power Query’s parallel processing. The engine may hit its default MaxDegreeOfParallelism limit (often 4 threads).
• Disk I/O Lag: If your system drive is SSD but nearly full (>90% capacity), or if you’re using a slow HDD, temporary files (like .iqy or .bin cache files) may not write/read in time, stalling the pipeline.

Pro Tip: ✨ Open Task Manager (Ctrl+Shift+Esc) and monitor Memory and CPU during the query. If RAM usage spikes to >80% or CPU hits 100%, close other apps or increase Excel’s memory allocation via File > Options > Advanced > Increase available heap size.

🔒 Data Source-Specific Issues

Not all data sources are created equal. Some platforms have quirks that break Power Query’s default connectors. Common offenders:

• API Rate Limiting: Many APIs (e.g., Twitter, Google Sheets) enforce rate limits (e.g., 100 requests/minute). Power Query may fire rapid successive calls, triggering a 429 Too Many Requests error, which it doesn’t handle gracefully.
• SSL/TLS Mismatches: Older servers with weak SSL certificates (e.g., SHA-1) or self-signed certs can cause Power Query’s System.Net.ServicePoint to reject the connection, even if the URL is correct.
• Dynamic Content or JavaScript: Web pages relying on JavaScript (e.g., SPAs like React) may not render data client-side. Power Query’s HTML scraper only sees the initial HTML, missing dynamically loaded tables.
• Authentication Failures: If the source requires OAuth 2.0 or multi-factor auth, Power Query’s built-in credentials manager may silently fail to refresh tokens, causing a 401 Unauthorized error.

Pro Tip: 💡 For APIs, check the source’s documentation for pagination or batch request limits. Use Web.Contents() with custom headers (e.g., Authorization: Bearer {token}) for manual control. For web pages, try ScraperAPI as an intermediary.

📁 Corrupted Query Cache or Metadata

Power Query stores intermediate steps and metadata in hidden files (e.g., *.bin in %LocalAppData%\Microsoft\Power Query). If these files corrupt—due to abrupt Excel crashes or permission issues—the query engine may fail to resume or initialize properly.

• Partial Cache Writes: If Excel crashes mid-query, the cache file may be left in an inconsistent state, causing Power Query to reject it on restart.
• Permission Denied: If your user account lacks write permissions to the cache folder, Power Query throws a System.UnauthorizedAccessException without a clear error message.
• Version Mismatch: Upgrading Excel/Power Query (e.g., from 2016 to 2021) can break older cache files, as the binary format evolves.

Pro Tip: 🔥 Clear the cache manually by deleting files in %LocalAppData%\Microsoft\Power Query\ (backup first!). To prevent future issues, enable File > Options > Data > Enable Power Query to load data from the web and set a refresh timeout of 60+ seconds.

How to solve it

Stuck at 99% with a Power Query download that won’t finish? Don’t panic—this is a common hiccup with clear solutions. Below, we’ve mapped the most likely causes to step-by-step fixes, plus tips to keep your queries running smoothly. Let’s get your data flowing again!

🔥 Cause 1: Network or Server Timeouts

If your download freezes at 99%, the connection might be dropping or timing out, especially with large datasets or slow servers.

• 🍳 Restart the connection: Close Power Query, restart Excel, and reopen your query. Sometimes a fresh start resolves temporary glitches.
• 👨‍🍳 Adjust timeout settings:
  1. Open Power Query Editor.
  2. Go to File > Options > Query Options.
  3. Under Global, increase the Command Timeout (try 30–60 seconds).
  4. Click _OK_ and retry.
• 🥘 Switch to a faster network: If working remotely, try switching to a wired connection or 5G instead of Wi-Fi.

💡 Prevention tip: For slow servers, pre-filter data in your source (e.g., SQL query or API call) to reduce load.

🔪 Cause 2: Corrupted Query or Cache Issues

A corrupted query file or cached data can cause Power Query to hang. This often happens after Excel crashes or updates.

• ⏰ Clear the query cache:
  1. Go to Home > Data > Queries & Connections.
  2. Right-click your query > Edit.
  3. Close the editor without saving changes.
  4. Reopen the query—this forces a fresh load.
• 🔄 Recreate the query: If clearing the cache doesn’t work, delete the query from the Queries & Connections pane, then rebuild it from scratch.
• 📁 Check for file corruption: Save your Excel file as a new workbook (File > Save As) to rule out file damage.

🎯 Prevention tip: Enable AutoSave in Excel (under File > Options > Save) to avoid losing progress during crashes.

🌡️ Cause 3: Large Data or Complex Transformations

Power Query may appear stuck if processing massive datasets or running heavy transformations (e.g., merging tables, grouping, or custom columns).

• 📊 Break the query into steps:
  1. Split your query into smaller chunks (e.g., load data in batches).
  2. Use Table.Buffer or Table.SelectRows to limit rows during testing.
• ✨ Optimize transformations:
  • Replace custom columns with Power Query functions where possible.
  • Avoid nested Table.NestedJoin operations—flatten data first.
  • Use Remove Errors or Fill Down sparingly on large tables.
• 💪 Increase system resources: Close other apps to free up RAM, or upgrade your machine if queries consistently struggle.

🔥 Prevention tip: For recurring large queries, schedule them to run overnight using Power Query + Power Automate.

⚠️ Bonus: When All Else Fails

If none of the above works, try these nuclear options:

• 🔄 Reset Power Query: Repair Office via Control Panel > Programs > Programs and Features.
• 📝 Contact Support: If the issue persists, report it to Microsoft with your Excel version and query steps.

Frequently asked questions